What an Amortization Schedule Shows

An amortization schedule is a loan table that shows how a debt is paid down over time. Each row usually represents one payment period. For a monthly loan, each row shows the month, payment amount, interest portion, principal portion, extra principal if any, and the remaining balance after the payment is applied. The schedule turns a loan from one large number into a clear series of smaller repayment steps.

This matters because a fixed monthly payment can hide how the loan actually behaves. At the beginning of a typical amortizing loan, the balance is high, so the interest charged for the month is high. A larger share of the payment goes to interest. Later in the loan, the balance is lower, so less interest is charged and more of the same monthly payment goes to principal. The payment may stay level, but the split inside the payment changes every month.

That shifting split is the main reason borrowers use an amortization table. It shows the true cost of time. A lower monthly payment can look attractive, but if it comes from a longer term, the borrower may pay much more total interest. A higher monthly payment can be harder on monthly cash flow, but it may reduce interest dramatically. A free amortization schedule calculator lets you compare these tradeoffs before signing a loan or deciding whether extra payments fit your plan.

Monthly Payment Formula

A standard fixed-rate amortizing loan uses the present value of an annuity formula. The loan amount is the present value. The monthly payment is the fixed payment that repays the principal and interest over the chosen number of months. The formula assumes a fixed monthly interest rate, a fixed number of payments, and a payment made each period.

In this formula, \(M\) is the scheduled monthly principal-and-interest payment, \(P\) is the loan principal, \(r\) is the monthly interest rate as a decimal, and \(n\) is the total number of monthly payments. If the annual interest rate is 6 percent, the monthly rate is 0.06 divided by 12, or 0.005. If the term is 30 years, the number of monthly payments is 360.

When the interest rate is zero, the formula simplifies. The payment is simply the loan amount divided by the number of payments. For example, a 12000 dollar loan at zero interest over 24 months would have a payment of 500 dollars. Most real loans charge interest, so the payment is higher than principal divided by months because the borrower must also pay the lender for the use of money over time.

How Each Row of the Schedule Is Calculated

After the monthly payment is known, the amortization table is generated one payment at a time. Interest for the month is calculated from the current outstanding balance. The principal portion is the scheduled payment minus that month's interest. If an extra principal payment is entered, the extra amount is added to principal reduction. The remaining balance becomes the starting balance for the next row.

If the scheduled principal plus extra payment would exceed the remaining balance, the final payment is reduced so the balance reaches zero rather than becoming negative. Lenders may handle final payoff amounts differently because of daily interest, fees, payment dates, and payoff quote rules. The calculator provides an estimate based on monthly amortization logic.

Why Interest Is Higher at the Beginning

Interest is based on the outstanding balance. At the start of a loan, the balance is close to the original principal, so the interest charge is large. Since the payment is fixed, a large interest charge leaves less of the payment for principal. As principal slowly declines, the next interest charge becomes slightly smaller. This allows a slightly larger share of the next payment to reduce principal. Over many months, the shift becomes significant.

For example, on a 250000 dollar loan at 6.5 percent for 30 years, the scheduled principal-and-interest payment is about 1580.17 dollars. The first month's interest is about 1354.17 dollars, leaving only about 226 dollars for principal. Years later, the balance is lower, so the interest portion is lower and the principal portion is higher. Near the end, most of the payment goes to principal.

This is not a trick in the schedule. It is the result of charging interest on the remaining balance. A borrower who understands this pattern can make better decisions about refinancing, extra payments, loan term, and total cost. A loan that feels slow at first may still be working normally, because early payments are carrying the largest interest burden.

Example Amortization Schedule

Suppose a borrower takes a 250000 dollar fixed-rate loan at 6.5 percent for 30 years. The monthly principal-and-interest payment is approximately 1580.17 dollars. The exact table generated by a lender may vary slightly because of rounding, payment due dates, escrow, and servicing conventions, but the core amortization logic is the same.

The first few rows make the pattern visible. The payment amount is constant, but the interest portion falls slightly each month and the principal portion rises slightly each month. The effect is small from one month to the next, but over years it becomes a major shift. That is why a full amortization table is more useful than a single monthly payment estimate.

What Extra Payments Do

Extra principal payments can reduce total interest because they lower the balance sooner. If the balance is lower, the next month's interest charge is lower. That leaves more of the scheduled payment available for principal. The effect compounds through the remaining life of the loan. Extra payments are usually most powerful earlier in the loan, when they have more months to reduce future interest.

However, extra payments are only useful if they are applied correctly. Some lenders apply extra money to future payments unless the borrower specifies principal reduction. Others have online options labeled "extra principal." Some loans may have prepayment penalties or restrictions. Before relying on estimated savings, confirm how your lender handles extra payments.

Suppose a borrower adds 100 dollars extra principal every month. The scheduled payment stays the same unless the loan is recast, but the balance falls faster. The calculator estimates how many months may be saved and how much interest may be avoided. These estimates depend on the assumptions staying constant: fixed rate, regular payment timing, and extra payment applied to principal.

Amortization Schedule vs Loan Calculator

A general loan calculator usually answers one question: what is the monthly payment? An amortization schedule answers a deeper question: what happens inside every payment? Both are useful, but they serve different purposes. If you are comparing several loan offers quickly, a loan calculator may be enough. If you want to see principal, interest, and balance across the term, use an amortization schedule.

This distinction helps avoid page overlap. This page is a table generator and schedule explainer. The personal loan calculator is better for personal-loan affordability and payment estimates. The auto loan calculator is better when vehicle price, down payment, trade-in, taxes, and loan term are the focus. The mortgage calculator is better for home-loan costs that may include taxes, insurance, and other housing expenses.

Principal and Interest vs Total Monthly Payment

An amortization schedule usually shows principal and interest, not every cost connected to a loan. This is especially important for mortgages. A mortgage payment may include principal, interest, property taxes, homeowners insurance, mortgage insurance, homeowners association dues, and other escrow items. The principal-and-interest payment is only one part of the total monthly housing cost.

For auto loans and personal loans, the scheduled payment may be closer to the actual monthly payment, but fees, add-ons, insurance products, and late charges can still affect the cost. For student loans, payment plans, deferment, capitalization, and income-driven repayment can make real schedules more complex than a standard fixed amortization table.

Use the calculator for the core debt repayment math. Then layer in the real-world costs from the loan estimate, promissory note, mortgage statement, auto finance agreement, or servicer account. A clear financial plan needs both: the amortization schedule and the full payment obligation.

APR, Interest Rate, and Amortization

The annual interest rate entered in this calculator is used to calculate monthly interest. APR is different. APR may include certain finance charges and fees, making it useful for comparing the cost of credit. The note rate or interest rate controls the monthly interest calculation in a standard amortization schedule, while APR is a disclosure measure for comparison.

If your loan documents show both an interest rate and an APR, do not assume they are interchangeable in an amortization table. The scheduled principal-and-interest payment is usually based on the note rate, not the APR. Fees included in APR may still be important for total cost, but they are not necessarily amortized the same way as principal.

Fixed-Rate Loans, Variable-Rate Loans, and Re-Amortization

This calculator is best for fixed-rate loans with regular monthly payments. In a fixed-rate fully amortizing loan, the interest rate is constant, the scheduled payment is constant, and the balance reaches zero at the end of the term if payments are made as scheduled. Many mortgages, auto loans, and personal loans follow this basic structure.

Variable-rate loans are different. If the interest rate changes, the amortization schedule must be recalculated using the new rate, remaining balance, and remaining term. Adjustable-rate mortgages, some student loans, and some lines of credit may not follow one fixed schedule from start to finish. A schedule printed at the beginning of a variable-rate loan is only a projection if future rates are unknown.

Re-amortization, sometimes called recasting in mortgage contexts, can also change the schedule. If a borrower makes a large principal payment and the lender recalculates the required monthly payment over the remaining term, the payment can fall while the maturity date stays similar. Not all lenders allow recasting, and rules vary. Extra payment without recasting usually shortens the payoff time instead of lowering the required payment.

Negative Amortization and Interest-Only Payments

Negative amortization happens when the payment is not enough to cover the interest owed. The unpaid interest is added to the balance, so the amount owed grows rather than falls. This is very different from a standard fully amortizing schedule. A borrower may be making payments and still owe more over time if the payments are too low to cover accruing interest.

Interest-only loans are also different from standard amortization. During the interest-only period, the borrower pays interest but does not reduce principal unless they make extra principal payments. When the interest-only period ends, payments may rise because the remaining balance must be repaid over a shorter remaining period. The calculator on this page is not designed to model interest-only or negative-amortization loans.

If a loan offers minimum payments, deferred interest, payment options, promotional financing, or interest-only periods, read the terms carefully. The monthly payment may look affordable while the long-term cost is much higher than a standard amortizing loan.

Using the Schedule to Compare Loan Terms

The loan term strongly affects the monthly payment and total interest. A longer term usually lowers the monthly payment but increases total interest. A shorter term usually raises the monthly payment but lowers total interest. The amortization schedule makes the tradeoff visible by showing the full path of payments, not only the first month's affordability.

When comparing offers, do not focus only on the lowest payment. A 72-month auto loan may have a lower payment than a 48-month auto loan, but it can keep the borrower in debt longer and increase total interest. A 30-year mortgage may be more affordable monthly than a 15-year mortgage, but the 15-year loan may save substantial interest if the payment fits the budget.

Reading the Monthly Payment Chart

A monthly payment chart should be read from left to right. Start with the payment number and date. Then look at the total payment amount. Next, compare the interest and principal columns. Finally, check the ending balance. The ending balance of one row becomes the starting balance for the next row. If extra principal is included, it should be shown separately so you can see how much of the balance reduction came from the scheduled payment and how much came from the extra amount.

The first rows reveal the loan's early interest burden. The middle rows show the crossover period, where principal becomes a larger share of the payment than interest. The final rows show the payoff mechanics, including a smaller adjusted final payment if the remaining balance is less than a full scheduled payment. A good amortization table makes all three periods visible.

Common Amortization Mistakes

• Using APR as the note rate: APR and interest rate are not always the same. Use the rate that controls the scheduled payment.
• Forgetting escrow costs: A mortgage amortization schedule usually shows principal and interest only, not taxes and insurance.
• Assuming extra payments lower the required payment: Extra principal often shortens payoff time unless the lender recasts the loan.
• Ignoring prepayment rules: Some loans may have prepayment penalties or lender-specific instructions for applying extra principal.
• Comparing only monthly payments: Low payments can hide high total interest if the term is long.
• Relying on an old schedule after a rate change: Variable-rate loans need updated schedules after rate adjustments.

How to Use an Amortization Schedule for Refinancing

Refinancing replaces an existing loan with a new loan. An amortization schedule helps you compare the old path and the new path. The key questions are: What is the new payment? How much interest remains on the current loan? How much interest would be paid on the new loan? What fees are required? How long will it take for monthly savings to recover the refinancing costs?

A lower payment does not automatically mean the refinance saves money. If the new loan restarts a long term, total interest can increase even though the monthly payment falls. If the borrower plans to sell, trade, or pay off the loan soon, upfront fees may not be recovered. The schedule helps by showing the remaining balance and total interest under each scenario.

How to Use an Amortization Schedule for Early Payoff

Borrowers often use amortization schedules to plan early payoff. Common strategies include adding a fixed extra amount every month, rounding the payment up, making one extra payment per year, applying bonuses or tax refunds to principal, or switching to biweekly payments. Each strategy works by reducing principal sooner, which reduces future interest.

Before choosing an early payoff strategy, compare it with other financial priorities. Paying extra on a low-rate loan may not be the best choice if the borrower has high-interest credit card debt, no emergency fund, employer retirement matching available, or upcoming cash needs. The schedule shows loan savings, but a full financial decision also considers liquidity, risk, and opportunity cost.

Loan Types This Calculator Can Help With

Related Finance Calculators

Use this page when the main task is to generate and understand a monthly amortization table. For adjacent finance tasks, use the page that matches the decision. The Compound Interest Calculator is better for savings or investment growth. The Simple Interest Calculator is better for interest that does not compound. The Auto Loan Calculator is better for vehicle-specific payment inputs. The Finance Calculators page can help when you need a broader tool list.

Checklist Before You Use the Results

1. Confirm whether the rate entered is the note interest rate, not only the APR.
2. Check the payment frequency. This page assumes monthly payments.
3. Confirm whether extra payments are applied to principal by the lender.
4. Remember that mortgage escrow, taxes, insurance, PMI, HOA dues, and fees are not included.
5. Use lender payoff quotes for final payoff amounts, because daily interest and fees can affect the exact amount.
6. Recalculate the schedule if the rate, term, principal, payment date, or extra payment strategy changes.
7. Compare total interest, not only monthly payment, when choosing between loans.

Monthly Table vs Yearly Summary

A monthly amortization table is the most detailed view because it shows every payment row. This is useful when you want to audit a specific month, compare the first payment with a later payment, estimate an early payoff date, or understand exactly when the interest portion drops below the principal portion. A monthly table is also useful when you make extra payments because it shows how each extra amount changes the next balance.

A yearly summary is better when you want a cleaner overview. Instead of reading 360 rows for a 30-year mortgage, a yearly summary groups 12 payments at a time. It can show total interest paid during the year, total principal paid during the year, ending balance, and cumulative interest. This is easier for planning because many borrowers think in annual budgets, tax years, and calendar-year goals.

The two views answer different questions. Monthly rows answer, "What happens in payment 37?" Yearly summaries answer, "How much principal did I pay down in year 5?" If you are comparing loans, the yearly view can quickly show how much balance remains after 3 years, 5 years, 7 years, or 10 years. If you are checking a lender statement, the monthly row is more useful because statements usually apply one payment at a time.

Key Columns in an Amortization Table

A useful amortization table should make the loan transparent. The payment number tells you where you are in the repayment timeline. The date helps connect the schedule to actual due dates. The payment column shows the amount paid that month. The interest column shows the lender's charge for that period. The principal column shows how much of the balance was reduced. The extra column, if present, separates voluntary principal reduction from the scheduled principal. The balance column shows what remains after the payment is applied.

Separating scheduled principal from extra principal is important. If a borrower pays 200 dollars extra every month, the total balance reduction is not the same as the normal scheduled principal. Without a separate extra column, it is harder to see what the original loan would have done and what the extra payment strategy changed. This also helps when comparing a lender statement with a personal spreadsheet.

The balance column is the anchor of the schedule. If the balance does not fall after a normal amortizing payment, something is wrong unless the loan has negative amortization, deferred interest, fees being added, or a payment that did not cover interest. For a standard fixed-rate fully amortizing loan, every scheduled payment should reduce the balance by at least some amount.

How to Reconcile a Schedule with a Lender Statement

An independent amortization calculator is useful, but a lender statement is the official record for a real loan. Differences can happen for normal reasons. Payment dates may not match exactly. Interest may accrue daily rather than strictly monthly. The lender may round each row differently. Escrow amounts may be included in the monthly draft. Fees, late charges, or payment reversals may appear. Extra payments may be applied differently from what the borrower expected.

To reconcile a schedule with a statement, start with the same opening balance and interest rate. Use the same payment date if interest is calculated daily. Confirm whether the scheduled payment includes only principal and interest or includes escrow. Check whether extra payments were posted as principal curtailments. If the lender statement shows a suspense account, partial payments may not have been credited to principal yet.

If the difference is small, rounding may explain it. If the difference is large, review the payment history. A skipped payment, late payment, fee, escrow adjustment, interest rate change, or incorrectly applied extra payment can change the schedule. Contact the servicer if a payment was not applied the way you intended. For mortgages, consumer servicing rules may affect how payments are credited, but your exact rights and procedures depend on the loan and jurisdiction.

Payment Frequency and Biweekly Payments

This calculator assumes monthly payments because monthly amortization is the standard format for many mortgages, auto loans, and personal loans. Some borrowers consider biweekly payments, where half of the monthly payment is made every two weeks. Because there are 52 weeks in a year, biweekly payments create 26 half-payments, which equals 13 full monthly payments per year. That extra annual payment can reduce interest and shorten the loan if the lender applies it correctly.

However, biweekly programs vary. Some servicers hold half-payments until a full monthly payment is available. Some third-party payment programs charge fees. Some borrowers can achieve a similar effect by making one extra principal payment per year or adding one-twelfth of a payment to each monthly payment. The math can be helpful, but the payment processing rules matter.

If you want to model biweekly payments with a monthly calculator, one practical approximation is to add one-twelfth of the scheduled monthly payment as extra principal each month. This simulates making one extra payment per year, although it may not match the exact timing of true biweekly processing. For a precise biweekly schedule, use a calculator specifically built around 26 half-payments per year and confirm lender treatment.

Payoff Quotes vs Calculator Balances

The balance shown in an amortization schedule is not always the same as a real payoff quote. A payoff quote is the amount required to fully satisfy the loan on a specific date. It may include interest accrued since the last payment, recording fees, statement fees, late fees, prepayment penalties if allowed, or other contract-specific items. A calculator balance is an estimate based on the assumptions entered.

This difference matters when selling a car, refinancing a mortgage, paying off a personal loan, or closing a home sale. If the calculator says the balance after payment 84 is 182000 dollars, the lender payoff quote for a particular date may be slightly higher or lower depending on daily interest and payment timing. Always use the lender's official payoff quote for final payoff transactions.

A calculator is still useful before requesting a quote because it helps you estimate where the balance should be. If the payoff quote is far from the expected schedule balance, ask for a breakdown. The difference may be legitimate, but it should be understandable.

Using Amortization for Mortgage Planning

Mortgage amortization is one of the most common uses of this calculator because mortgages are often large, long-term, and interest-heavy in the early years. A 30-year fixed mortgage can have 360 monthly payments. Even a small rate difference can create a large total interest difference over that many payments. The schedule helps borrowers see how much interest is paid in the first year, how slowly the balance falls early on, and how much faster principal reduction becomes later.

Mortgage borrowers should remember that the amortization schedule usually shows principal and interest only. The actual monthly mortgage payment may also include property taxes, homeowners insurance, mortgage insurance, flood insurance, HOA dues, or escrow shortages. When planning affordability, use the full housing payment. When studying principal reduction and interest cost, use the amortization schedule.

Amortization also helps with refinancing decisions. A borrower who has already paid several years on a 30-year mortgage may not want to restart another 30-year clock without comparing total interest. A lower payment can improve cash flow, but it may extend debt. Comparing the current remaining schedule with the proposed new schedule is more useful than comparing monthly payments alone.

Using Amortization for Auto Loans

Auto loans usually have shorter terms than mortgages, but amortization still matters. Vehicle loans may run 36, 48, 60, 72, or 84 months. Longer terms reduce the monthly payment but can increase total interest and increase the risk of owing more than the vehicle is worth for longer. The schedule shows how quickly the balance falls, which can be useful when planning trade-in timing or deciding how much down payment is appropriate.

Auto-loan borrowers should also consider depreciation. An amortization schedule shows loan balance, not vehicle value. A car can lose value faster than the loan balance falls, especially with a small down payment, long term, or high interest rate. If the loan balance exceeds the vehicle value, the borrower has negative equity. The amortization table helps estimate the loan side of that comparison.

Extra principal can be useful on auto loans when the borrower wants to reduce interest, shorten the term, or get out of negative equity sooner. Before paying extra, check whether the lender applies extra money to principal and whether there are any prepayment restrictions.

Using Amortization for Personal Loans

Personal loans often have fixed rates, fixed payments, and terms from a few years to several years. Because personal loans can carry higher rates than secured loans, the amortization schedule can reveal how much the loan actually costs. A payment may look manageable, but total interest can still be significant if the rate is high or the term is long.

When comparing personal loan offers, look at the loan amount, interest rate, APR, fees, term, monthly payment, and total paid. The amortization schedule helps with the principal-and-interest path, but origination fees and other charges may affect the real cost. A lower monthly payment may simply mean a longer repayment period.

If a personal loan is being used for debt consolidation, compare the schedule with the debts being consolidated. The new payment may be simpler, but the total cost depends on rate, term, fees, and repayment behavior. Avoid using a lower payment as permission to rebuild the old balances.

Using Amortization for Education Loans

Education loans can be more complex than standard amortizing loans because repayment plans may include grace periods, deferment, forbearance, income-driven payments, capitalization, subsidies, and changing payment amounts. A standard amortization schedule is still useful when the loan behaves like a fixed-rate loan with a set repayment term, but it may not capture every student-loan feature.

If interest accrues during school or deferment and is later capitalized, the principal balance used in the schedule can increase. If payments are income-driven, the monthly payment may not match the standard amortization formula. If the payment does not cover interest, the balance may not fall as expected. For education loans, use official servicer tools and loan documents alongside any independent calculator.

Spreadsheet-Friendly Amortization Fields

If you want to recreate the schedule in a spreadsheet, use consistent columns. A clean spreadsheet may include payment number, payment date, beginning balance, scheduled payment, interest rate, interest amount, scheduled principal, extra principal, total principal, ending balance, cumulative interest, and cumulative principal. Keeping the fields separate makes it easier to audit formulas.

A common spreadsheet pattern is to reference the prior row's ending balance as the next row's beginning balance. The interest amount is beginning balance times monthly rate. Principal is payment minus interest. Ending balance is beginning balance minus principal minus extra principal. The final row needs a cap so the payment does not exceed the remaining balance plus interest.

When building your own spreadsheet, test it against known values from the calculator. If the first payment, total interest, and final payoff month are close, the structure is probably correct. If the balance goes negative early or never reaches zero, check the rate conversion, payment formula, and final-payment adjustment.

Rounding and Final Payment Differences

Rounding is one reason amortization schedules can differ by a few cents. The mathematical payment may have many decimal places, but real payments are made in cents. Some schedules round the monthly payment first and then calculate each row. Others keep more internal precision and round only displayed values. Over hundreds of payments, tiny rounding differences can change the final payment slightly.

The final payment is often adjusted to clear the remaining balance exactly. If the regular payment is 1580.17 dollars but only 742.31 dollars is needed to cover the final interest and principal, the final payment should be lower in the estimate. In real life, the lender's payoff amount may include daily interest through a payoff date, so the official final number can differ from the displayed schedule.

What the Calculator Does Not Include

A clear calculator should state its limits. This amortization schedule does not include taxes, insurance, escrow, mortgage insurance, HOA dues, origination fees, discount points, closing costs, registration fees, optional warranties, late fees, or daily interest payoff adjustments. It does not model adjustable rates, interest-only periods, skipped payments, negative amortization, balloon payments, or income-driven payment plans.

Those limitations do not make the calculator useless. They keep the calculator focused on the core amortization engine: principal, interest, payment, balance, and term. Once that core is understood, borrowers can add the surrounding loan costs from official documents. Mixing every possible fee into one table can make the schedule harder to read and easier to misunderstand.

Frequently Asked Questions

What is an amortization schedule?

An amortization schedule is a table that shows how each loan payment is split between interest and principal, and how the remaining balance falls after each payment. It is commonly used for mortgages, auto loans, personal loans, and other fixed repayment loans.

How do I calculate a monthly loan payment?

Use the standard amortizing loan formula: payment equals principal times monthly rate times \((1+r)^n\), divided by \((1+r)^n-1\). The calculator handles this automatically after you enter principal, annual interest rate, and term.

Why does my first payment mostly go to interest?

Interest is calculated on the current balance. At the beginning, the balance is highest, so the interest charge is highest. As the balance falls, the interest portion decreases and the principal portion increases.

Does making extra payments change my monthly payment?

Usually, extra principal payments shorten the payoff time and reduce interest, but they do not automatically lower the required monthly payment. A lender may need to recast or re-amortize the loan to lower the required payment.

Does this calculator include taxes and insurance?

No. The calculator estimates principal and interest amortization only. Mortgage taxes, homeowners insurance, PMI, HOA dues, escrow changes, and fees are separate costs.

Can I use this for an auto loan?

Yes, if the auto loan has a fixed rate, fixed term, and regular monthly payments. For vehicle-specific inputs such as down payment and trade-in, the auto loan calculator may be more useful.

Can I use this for a mortgage?

Yes, for principal-and-interest amortization. For a fuller housing payment estimate that includes mortgage-specific costs, use a mortgage calculator and review lender documents.

What is negative amortization?

Negative amortization means the payment is not enough to cover the interest owed, so unpaid interest is added to the balance. The balance can grow even while payments are being made.

Why does the final payment sometimes differ from the regular payment?

The final payment may be smaller because the remaining balance plus final interest is less than a full scheduled payment. Real lender payoff amounts can also include daily interest and fees.

Is this calculator financial advice?

No. It is an educational calculator for estimating loan amortization. Borrowing, refinancing, extra payment, and payoff decisions should be based on loan documents, lender guidance, and qualified professional advice where needed.

Source Notes

This page uses standard fixed-rate amortization math. For consumer context on amortizing loans, principal, interest, mortgage payments, negative amortization, and payment servicing, see the CFPB explanation of amortization, CFPB mortgage payoff explanation, CFPB principal and interest payment explanation, and CFPB negative amortization explanation. These references are provided for educational context; this calculator does not provide financial, tax, legal, or lending advice.