Time Calculator: Hours, Timesheet & Payroll Calculator
A time calculator is an essential workforce management tool that accurately computes work hours, time duration between dates, clock in/out times with lunch breaks, decimal hour conversions for payroll processing, billable hours tracking, and working days calculations. By using precise time arithmetic, military time conversion, and automated timesheet calculations, this calculator helps employers process payroll accurately, employees track work hours, freelancers calculate billable time, project managers monitor labor hours, and accountants verify time-based compensation for payroll systems, employee timesheets, contractor billing, project time tracking, and labor cost analysis across various industries and pay periods.
🕐 Interactive Time Calculator
Calculate work hours, payroll time, and date differences
Time Clock Calculator with Breaks
Calculate total work hours with lunch breaks
Weekly Timesheet Calculator
Calculate total weekly work hours
Time to Decimal Hours Converter
Convert time to decimal format for payroll
Working Days Calculator
Calculate business days between dates
Time Duration Calculator
Calculate difference between two times or dates
Understanding Time Calculations
Time calculations involve computing durations, converting between time formats, and performing arithmetic operations on time values. Accurate time tracking is essential for payroll processing, project management, and billing purposes.
Work Hours Calculation Formula
Total Work Hours Formula:
\[ H_{\text{work}} = H_{\text{out}} - H_{\text{in}} - B_{\text{breaks}} \]
Where:
\[ H_{\text{work}} = \text{Total work hours} \]
\[ H_{\text{out}} = \text{Clock out time} \]
\[ H_{\text{in}} = \text{Clock in time} \]
\[ B_{\text{breaks}} = \text{Total break time} \]
Work Hours Example
Calculate Daily Work Hours
Clock In: 9:00 AM
Clock Out: 5:00 PM
Lunch Break: 30 minutes
Step 1: Total time = 5:00 PM - 9:00 AM = 8 hours
Step 2: Subtract lunch = 8 hours - 0.5 hours = 7.5 hours
Result: 7.5 work hours (7 hours 30 minutes)
Decimal: 7.50 hours for payroll
Time to Decimal Conversion Formula
Convert Minutes to Decimal Hours:
\[ D = H + \frac{M}{60} \]
Where:
\[ D = \text{Decimal hours} \]
\[ H = \text{Whole hours} \]
\[ M = \text{Minutes} \]
Examples:
8:30 = 8 + (30÷60) = 8.50 hours
7:45 = 7 + (45÷60) = 7.75 hours
Time Conversion Reference Chart
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| :00 | .00 | :30 | .50 |
| :05 | .08 | :35 | .58 |
| :10 | .17 | :40 | .67 |
| :15 | .25 | :45 | .75 |
| :20 | .33 | :50 | .83 |
| :25 | .42 | :55 | .92 |
Complete Decimal Conversion Table
| Time Format | Decimal Hours | Time Format | Decimal Hours |
|---|---|---|---|
| 8:00 | 8.00 | 8:30 | 8.50 |
| 8:15 | 8.25 | 8:45 | 8.75 |
| 9:00 | 9.00 | 9:30 | 9.50 |
| 10:00 | 10.00 | 10:30 | 10.50 |
| 7:30 | 7.50 | 7:45 | 7.75 |
Military Time Conversion
| Standard Time | Military Time | Standard Time | Military Time |
|---|---|---|---|
| 12:00 AM | 00:00 | 12:00 PM | 12:00 |
| 1:00 AM | 01:00 | 1:00 PM | 13:00 |
| 6:00 AM | 06:00 | 6:00 PM | 18:00 |
| 9:00 AM | 09:00 | 9:00 PM | 21:00 |
| 11:59 AM | 11:59 | 11:59 PM | 23:59 |
Standard Work Schedules
| Schedule Type | Hours Per Day | Hours Per Week | Break Time |
|---|---|---|---|
| Full-Time (Standard) | 8 hours | 40 hours | 30-60 min lunch |
| Part-Time | 4-6 hours | 20-30 hours | 15-30 min break |
| Compressed Week | 10 hours | 40 hours (4 days) | 60 min lunch |
| Flex Schedule | Variable | 40 hours | Variable |
| 12-Hour Shifts | 12 hours | 36-48 hours | Multiple breaks |
Payroll Time Calculation
Weekly Payroll Formula
Weekly Pay Calculation:
\[ P_{\text{weekly}} = H_{\text{total}} \times R_{\text{hourly}} \]
With Overtime:
\[ P_{\text{total}} = (H_{\text{regular}} \times R) + (H_{\text{OT}} \times R \times 1.5) \]
Where overtime = hours over 40 per week (US standard)
Biweekly Timesheet Example
Calculate Biweekly Hours
Week 1: 40 hours
Week 2: 38 hours
Total Hours: 78 hours
At $20/hour: 78 × $20 = $1,560
If Week 1 had 42 hours:
• Regular: 40 hours × $20 = $800
• Overtime: 2 hours × $30 (1.5×) = $60
• Week 1 Total: $860
Working Days Calculation
Business Days Formula
Working Days (Mon-Fri):
\[ W = \left\lfloor \frac{D}{7} \right\rfloor \times 5 + R_{\text{adj}} \]
Where:
\[ W = \text{Working days} \]
\[ D = \text{Total calendar days} \]
\[ R_{\text{adj}} = \text{Adjustment for remaining days} \]
Break Time Requirements
| Shift Length | Meal Break | Rest Breaks | Total Unpaid Time |
|---|---|---|---|
| 4 hours | None required | 1 × 10 min | 0 minutes |
| 6 hours | 30 min lunch | 1 × 10 min | 30 minutes |
| 8 hours | 30-60 min lunch | 2 × 10 min | 30-60 minutes |
| 10 hours | 60 min lunch | 3 × 10 min | 60 minutes |
| 12 hours | 2 × 30 min | 3 × 15 min | 60 minutes |
Note: Break requirements vary by jurisdiction. Check local labor laws.
Practical Applications
Payroll Processing
- Time card verification: Validate employee clock in/out records
- Overtime calculation: Track hours exceeding standard work week
- Decimal conversion: Convert time to decimal format for payroll systems
- Billable hours: Calculate client billing for hourly services
- Labor cost analysis: Determine total labor expenses per project
- Compliance reporting: Ensure adherence to labor regulations
Project Management
- Time tracking: Monitor hours spent on tasks and projects
- Resource allocation: Calculate available work hours for assignments
- Deadline management: Determine working days until project completion
- Budget tracking: Compare actual vs. estimated labor hours
- Productivity metrics: Analyze time efficiency and utilization rates
- Client reporting: Generate time summaries for invoicing
Employee Management
- Attendance tracking: Record daily work hours and patterns
- Schedule planning: Create shift schedules with proper coverage
- Leave calculation: Track vacation and sick time usage
- Timesheet approval: Verify accuracy of submitted hours
- Overtime monitoring: Manage and control overtime costs
- Performance review: Analyze work hour patterns and punctuality
Time Tracking Best Practices
Accurate Time Tracking Guidelines:
- Clock in/out consistently: Use same system daily for accuracy
- Record breaks properly: Track all unpaid lunch and rest periods
- Round appropriately: Follow company policy (nearest 5, 10, or 15 minutes)
- Document exceptions: Note early departures, late arrivals, absences
- Review regularly: Check timesheets weekly before submission
- Use decimal format: Convert to decimals for payroll processing
- Keep records: Maintain copies for tax and legal purposes
- Report discrepancies: Address errors immediately with supervisor
Common Calculation Errors
⚠️ Avoid These Mistakes
- Forgetting break deductions: Must subtract unpaid lunch time
- Incorrect decimal conversion: 8:30 is 8.50, not 8.30
- AM/PM confusion: Verify morning vs afternoon times
- Not accounting for midnight: Shifts crossing midnight need special handling
- Rounding errors: Improper rounding affects payroll accuracy
- Overtime miscalculation: Must calculate at 1.5× rate after 40 hours
- Including paid breaks: Only deduct unpaid break time
- Military time errors: 2:00 PM is 14:00, not 2:00
Frequently Asked Questions
How do I calculate work hours with lunch break?
Subtract clock in time from clock out time, then deduct lunch break. Example: Work 9 AM to 5 PM (8 hours) minus 30-minute lunch = 7.5 hours or 7:30. In decimal: 7.50 hours. Formula: (Clock out - Clock in) - Break time. Most employers require 30-60 minute unpaid lunch for 8-hour shifts.
How do I convert time to decimal for payroll?
Divide minutes by 60 and add to hours. Formula: Decimal = Hours + (Minutes ÷ 60). Examples: 8:15 = 8 + (15÷60) = 8.25 hours; 7:30 = 7 + (30÷60) = 7.50 hours; 8:45 = 8 + (45÷60) = 8.75 hours. Common conversions: :15 = .25, :30 = .50, :45 = .75.
What are working days vs calendar days?
Working days (business days) count Monday-Friday excluding weekends and holidays. Calendar days include all days. Example: 10 calendar days starting Monday = next Wednesday (includes weekend). 10 working days = 2 weeks from Monday (excludes 4 weekend days). Project deadlines typically use working days; contracts may specify calendar days.
How do I calculate overtime hours?
Overtime = hours worked beyond 40 per week (US standard). Paid at 1.5× regular rate. Example: 45 hours worked. Regular: 40 hours × $20 = $800. Overtime: 5 hours × $30 (1.5×$20) = $150. Total = $950. Some states require daily overtime (over 8 hours/day). Check local laws.
What is military time and how do I convert it?
Military time uses 24-hour format (00:00-23:59) without AM/PM. Convert: AM hours stay same (9:00 AM = 09:00); PM hours add 12 (2:00 PM = 14:00, 5:00 PM = 17:00). Midnight = 00:00, noon = 12:00. Used in healthcare, military, international business for clarity and avoiding AM/PM confusion.
How do I calculate biweekly timesheet hours?
Add total hours for both weeks. Example: Week 1: Mon-Fri (8+8+8+8+7.5 = 39.5 hours), Week 2: Mon-Fri (8+8+8+8+8 = 40 hours). Biweekly total = 79.5 hours. Calculate overtime separately per week if hours exceed 40. Most payroll systems use biweekly (every 2 weeks) or semi-monthly (twice per month) pay periods.
Key Takeaways
Accurate time calculation requires understanding time arithmetic, decimal conversion, break deductions, and proper recording methods. Time tracking is essential for fair compensation, legal compliance, and effective workforce management.
Essential principles to remember:
- Work hours = Clock out - Clock in - Breaks
- Decimal hours = Hours + (Minutes ÷ 60)
- :15 minutes = .25 hours, :30 = .50, :45 = .75
- Full-time standard = 40 hours per week
- Overtime (US) = hours over 40 per week at 1.5× rate
- Working days exclude weekends and holidays
- Military time: PM hours add 12 (2 PM = 14:00)
- Lunch breaks typically 30-60 minutes unpaid
- Round time per company policy (5, 10, or 15 minutes)
- Keep accurate records for payroll and legal compliance
Getting Started: Use the interactive time calculator at the top of this page to calculate work hours with breaks, convert time to decimal format for payroll, create weekly timesheets, determine working days between dates, or calculate time duration. Select your calculation type, enter the times or dates, and receive instant accurate results with detailed breakdowns for payroll processing and time tracking.
