Time Calculator: Add, Subtract & Track

To calculate elapsed time, subtract the start time from the end time. Ensure both times are in a consistent format (e.g., HH:MM:SS or decimal hours).

• Example (HH:MM): End Time: 14:30, Start Time: 09:15.
  • Minutes: 30 - 15 = 15 minutes.
  • Hours: 14 - 9 = 5 hours.
  • Elapsed time: 5 hours and 15 minutes.
• If crossing midnight, it's often easier to calculate time to midnight, then add the time from midnight to the end time, or add 24 hours to the end time if it's on the next day before subtracting.
• For tasks like "what time will my movie end?", you add a duration to a start time: Start Time + Duration = End Time.

Time and a half pay is 1.5 times an employee's regular hourly rate, typically for hours worked over a standard threshold (e.g., 40 hours per week).

Formula: Overtime Pay = (Regular Hourly Rate × 1.5) × Overtime Hours Worked

Example: If regular rate is $20/hour and an employee works 5 overtime hours:

• Overtime rate: $20 × 1.5 = $30/hour.
• Total overtime pay: $30 × 5 hours = $150.

Eligibility for overtime, including for salaried employees, depends on local labor laws and employment contracts.

Double time pay is twice an employee's regular hourly rate. It's often paid for working on specific holidays, exceptionally long shifts, or as per union agreements or company policy.

Formula: Double Time Pay = (Regular Hourly Rate × 2) × Double Time Hours Worked

Example: If regular rate is $20/hour and an employee works 8 double time hours:

• Double time rate: $20 × 2 = $40/hour.
• Total double time pay: $40 × 8 hours = $320.

Excel stores time as a fraction of a 24-hour day (e.g., 12:00 PM is 0.5, 6:00 AM is 0.25).

• Entering Time: Type in formats like 9:30 AM or 17:45. Excel will recognize it as time.
• Calculating Duration: Subtract the start time cell from the end time cell (e.g., =B2-A2). Format the result cell using a custom format like [h]:mm:ss or [h]:mm to correctly display durations, especially those over 24 hours.
• Adding/Subtracting Durations: You can add or subtract time values. Example: To add 3 hours and 30 minutes to the time in cell A2, use =A2 + TIME(3,30,0).
• Time Difference Over Days/Months/Years: Use the DATEDIF(start_date, end_date, "unit") function. "Unit" can be "d" (days), "m" (months), "y" (years), etc.
• Convert to Decimal Hours: If cell A2 contains a time (e.g., 8:15 for 8 hours and 15 minutes), multiply by 24: =A2*24. Format the result cell as a Number. (8:15 AM would become 8.25).

The relationship is Speed = Distance / Time. To find time, rearrange the formula:

Formula: Time = Distance / Speed

Ensure your units are consistent. If speed is in miles per hour (mph), distance should be in miles, and the resulting time will be in hours.

Example: If distance is 150 km and average speed is 50 km/hour:

• Time = 150 km / 50 km/h = 3 hours.

Military time, or the 24-hour clock, runs from 00:00 (midnight) to 23:59.

• From AM/PM to Military Time:
  • 12:00 AM (midnight) to 12:59 AM: Subtract 12 hours. (12:30 AM becomes 00:30).
  • 1:00 AM to 11:59 AM: Hours and minutes remain the same (e.g., 9:30 AM is 09:30). Add a leading zero for hours less than 10.
  • 12:00 PM (noon) to 12:59 PM: Hours and minutes remain the same (e.g., 12:30 PM is 12:30).
  • 1:00 PM to 11:59 PM: Add 12 to the hour (e.g., 3:30 PM becomes 15:30).
• From Military Time to AM/PM:
  • 00:00 to 00:59: Add 12 to the hour, it's AM (e.g., 00:45 is 12:45 AM).
  • 01:00 to 11:59: It's AM (e.g., 09:30 is 9:30 AM).
  • 12:00 to 12:59: It's PM (e.g., 12:45 is 12:45 PM).
  • 13:00 to 23:59: Subtract 12 from the hour, it's PM (e.g., 17:45 is 5:45 PM).

Accurate calculation of time worked is crucial for payroll.

1. Record Precise Start and End Times: For each work shift.
2. Calculate Daily Hours Worked: Subtract the start time from the end time. Remember to deduct any unpaid breaks.
3. Convert Minutes to Decimal Hours: This is standard for payroll systems. Divide the total minutes worked by 60.
   • Example: 45 minutes = 45/60 = 0.75 hours.
   • Example: 7 hours and 30 minutes = 7 + (30/60) = 7.5 hours.
4. Sum Total Decimal Hours: Add up all decimal hours for the entire pay period.
5. Apply Pay Rate: Multiply the total decimal hours by the employee's hourly rate. Factor in any overtime or double time rates as applicable.

FTE measures how many full-time positions are equivalent to the hours worked by all employees (full-time and part-time).

1. Define a Full-Time Workload: Determine the standard hours for a full-time employee in your organization (e.g., 40 hours/week or 2,080 hours/year).
2. Sum All Hours Worked: Add up the total hours worked by all employees (both full-time and part-time) during a specific period.
3. Calculate FTE: Divide the total hours worked by the standard full-time workload for that period.

Formula: FTE = Total Hours Worked by All Employees / Standard Full-Time Hours for Period

Alternatively, for part-time focus: Sum part-time hours, divide by full-time standard, then add the count of full-time employees.

Doubling time is the period it takes for a quantity (like an investment or population) to double in size or value, assuming a constant growth rate.

• Rule of 70 (Approximation): For quick estimates with percentage growth rates:

  Doubling Time ≈ 70 / Growth Rate (as a percentage)

  Example: If an investment grows at 7% per year, it will double in approximately 70 / 7 = 10 years.

• Precise Formula (using natural logarithm):

  Doubling Time (t) = ln(2) / ln(1 + r)

  Where ln is the natural logarithm and r is the growth rate per period expressed as a decimal (e.g., 7% growth is r = 0.07).

These are core concepts in kinematics (the study of motion):

• Displacement (d or Δx): Change in position. It's a vector quantity.
• Velocity (v): The rate of change of displacement. Average velocity v_avg = Δx / Δt. It's a vector. Speed is the magnitude of velocity.
• Acceleration (a): The rate of change of velocity. Average acceleration a_avg = Δv / Δt. It's a vector.

Key Formulas (for constant acceleration):

• v = v₀ + at (final velocity = initial velocity + acceleration × time)
• Δx = v₀t + ½at² (displacement = initial velocity × time + ½ × acceleration × time²)
• v² = v₀² + 2aΔx (final velocity² = initial velocity² + 2 × acceleration × displacement)

From Graphs:

• Displacement-Time Graph: The slope at any point gives the instantaneous velocity.
• Velocity-Time Graph:
  • The slope at any point gives the instantaneous acceleration.
  • The area under the graph (between the curve and the time axis) gives the displacement.

PTO accrual methods vary significantly by employer. Common methods include:

• Fixed Amount Per Pay Period: Employees earn a set number of PTO hours each paycheck (e.g., 3.08 hours bi-weekly for 10 days of PTO per year).
• Per Hour Worked: Employees earn a fraction of PTO for each hour worked (e.g., if a full-time year is 2080 hours and annual PTO is 80 hours, accrual rate is 80/2080 ≈ 0.03846 hours of PTO per hour worked).
• Lump Sum: Employees receive their entire annual PTO allowance at once, typically at the beginning of the year or on their work anniversary.
• Tiered System: Accrual rates often increase based on an employee's length of service (years at the company).

Always refer to your company's employee handbook or HR department for the specific PTO accrual policy applicable to you.

Zulu Time is another name for Coordinated Universal Time (UTC), the global time standard. To calculate it from your local time:

1. Determine your local time zone's offset from UTC. For example:
   • Eastern Standard Time (EST) is UTC-5 hours.
   • Pacific Standard Time (PST) is UTC-8 hours.
   • Central European Time (CET) is UTC+1 hour.
   • Note: Daylight Saving Time (DST) changes these offsets (e.g., EDT is UTC-4).
2. Convert your local time to UTC:
   • If your offset is negative (e.g., UTC-5), add the offset hours to your local time. (Example: 2 PM EST [UTC-5] is 2 PM + 5 hours = 7 PM UTC or 19:00 UTC).
   • If your offset is positive (e.g., UTC+1), subtract the offset hours from your local time. (Example: 2 PM CET [UTC+1] is 2 PM - 1 hour = 1 PM UTC or 13:00 UTC).

Many online tools and smartphone clocks can display UTC directly.

Cycle Time is the total time it takes to complete one full cycle of an operation or to produce one unit, from start to finish.

Formula: Cycle Time = Process End Time – Process Start Time (for a single unit or cycle)

It's a key metric in manufacturing and process improvement, indicating the actual time spent working on a unit or task. Reducing cycle time often leads to increased efficiency and output.

Takt Time is the rate at which products or services must be produced to meet customer demand. It aligns production pace with sales rate.

Formula: Takt Time = Net Available Production Time per Period / Customer Demand per Period

• Net Available Production Time: Total shift time minus breaks, meetings, maintenance, etc.
• Customer Demand: Number of units required by customers in that same period.

Example: If a factory operates for 450 minutes (net) per day and daily customer demand is 90 units:

• Takt Time = 450 minutes / 90 units = 5 minutes per unit.

This means a unit must be completed every 5 minutes to meet customer demand.

The Times Interest Earned (TIE) ratio measures a company's ability to meet its interest payment obligations on its debt. It's an indicator of financial health.

Formula: TIE Ratio = EBIT / Interest Expense

• EBIT: Earnings Before Interest and Taxes. Found on the income statement.
• Interest Expense: The company's cost of borrowing money. Found on the income statement.

A higher TIE ratio suggests the company has more earnings available to cover its interest payments, indicating lower risk for lenders.

Google Maps uses a complex combination of factors to estimate travel times:

• Road Network Data: Detailed information about roads, including speed limits, number of lanes, road types (highway, city street), and one-way streets.
• Historical Traffic Patterns: Average traffic speeds on different road segments at various times of day and days of the week, based on past data.
• Real-Time Traffic Data: Anonymized location data from smartphones and sensors helps Google understand current traffic conditions, including congestion, accidents, and slowdowns.
• User-Reported Incidents: Information from users about accidents, construction, speed traps, etc.
• Algorithms: Sophisticated routing algorithms (like variations of A* or Dijkstra's) analyze possible routes, factoring in distance, speed, current traffic, and predicted traffic.
• Mode of Transport: Calculations differ significantly for driving, walking, cycling, or public transit (which includes schedules and real-time transit data where available).
• Predictive Modeling: For future departures, Google may use predictive models based on historical data to estimate traffic conditions.

The estimate is dynamic and can change based on evolving conditions.