Time Card Calculator: Decimal Hours & Overtime Guide
Calculate work hours from clock-in and clock-out times. Convert minutes to decimal hours, track overtime, and handle lunch breaks with a full decimal chart.
Time Card Calculator — Direct Answer
A time card calculator converts clock-in and clock-out times into decimal hours for payroll. 8:30 AM to 5:00 PM with a 30-minute lunch = 8.0 hours. Minutes convert to decimals by dividing by 60: 30 min = 0.5, 15 min = 0.25, 45 min = 0.75. Add all days, then multiply by hourly rate.
→ Calculate work hours with our free hours calculator
How to Calculate Work Hours
Every time card problem follows the same steps: subtract times, convert minutes to decimals, sum days.
Hours = (Clock Out − Clock In) − Unpaid Break
Decimal Hours = Hours + (Minutes ÷ 60)
Where:
- Clock Out = end of shift (in 24-hour format)
- Clock In = start of shift
- Unpaid Break = lunch or personal time (not paid)
How to convert minutes to decimal hours
| Minutes | Decimal |
|---|---|
| 5 | 0.08 |
| 10 | 0.17 |
| 15 | 0.25 |
| 20 | 0.33 |
| 25 | 0.42 |
| 30 | 0.50 |
| 35 | 0.58 |
| 40 | 0.67 |
| 45 | 0.75 |
| 50 | 0.83 |
| 55 | 0.92 |
| 60 | 1.00 |
How to apply the formula
Example: Monday shift 8:15 AM to 5:30 PM with 30-min lunch
- Clock in = 8.25 (8:15 AM)
- Clock out = 17.50 (5:30 PM)
- Gross = 17.50 − 8.25 = 9.25 hours
- Subtract lunch = 9.25 − 0.50 = 8.75 hours
Example: Tuesday shift 7:00 AM to 4:45 PM with 45-min lunch
- Clock in = 7.00
- Clock out = 16.75
- Gross = 9.75
- Minus lunch = 9.30 hours
Weekly Timesheet Example
| Day | In | Out | Lunch | Hours |
|---|---|---|---|---|
| Mon | 8:00 | 5:00 | 30 min | 8.50 |
| Tue | 8:15 | 5:30 | 30 min | 8.75 |
| Wed | 8:00 | 5:00 | 30 min | 8.50 |
| Thu | 7:45 | 4:45 | 30 min | 8.50 |
| Fri | 8:00 | 6:00 | 30 min | 9.50 |
| Total | 43.75 |
Calculation:
- Regular: 40 hours
- Overtime: 3.75 hours
- Overtime rate: 1.5×
Overtime Rules (FLSA)
Federal requirements
| Rule | Requirement |
|---|---|
| Overtime threshold | 40 hours/week |
| Overtime rate | 1.5× regular |
| Double time | Not federally required |
| Weekly vs daily | Weekly (unless state requires daily) |
State-specific rules
| State | Daily OT | Weekly OT |
|---|---|---|
| California | 8+ hrs/day | 40+ hrs/week |
| Alaska | 8+ hrs/day | 40+ hrs/week |
| Nevada | 8+ hrs/day | 40+ hrs/week |
| Colorado | 12+ hrs/day | 40+ hrs/week |
| Most other states | — | 40+ hrs/week |
Overtime calculation
Example: $20/hr, 45 hours worked
- Regular: 40 × $20 = $800
- Overtime: 5 × $20 × 1.5 = $150
- Total: $950
Common Time Card Mistakes
Mistake 1: Using minutes instead of decimals
Entering "8.30" for 8:30 AM (should be 8.50) causes a 20-minute payroll error per shift. Fix: Convert minutes ÷ 60 to get decimals. 30 min = 0.50.
Mistake 2: Forgetting unpaid breaks
A 30-minute paid lunch is not standard. Most employers deduct lunch. Fix: Confirm with your employer — most breaks over 20 minutes are unpaid.
Mistake 3: Rounding wrong
Rounding 8:08 to 8:15 loses or gains 7 minutes. This compounds over 260 workdays. Fix: Use decimal to 2 places (0.01 hour = 36 seconds). Don't round unless required.
Time Card vs Time Clock vs Timesheet
Time card
- Format: Weekly punch-in/out record
- Use: Hourly employees
- Best for: Manual tracking
Time clock
- Format: Physical or digital punch system
- Use: Employee tracking
- Best for: Automation
Timesheet
- Format: Detailed task or project breakdown
- Use: Contractors, freelancers
- Best for: Billable hours
Time Card Calculator FAQ
How do I calculate time card hours?
Subtract clock-in from clock-out, convert minutes to decimals, sum across days. 8:30 AM to 5:00 PM with 30-min lunch = 8.0 hours.
How do I convert minutes to decimals for payroll?
Divide minutes by 60. 15 min = 0.25, 30 min = 0.50, 45 min = 0.75.
What is 8 hours 30 minutes in decimal?
8.50 hours. 30 ÷ 60 = 0.50.
How do I calculate overtime?
Hours over 40 per week are paid at 1.5× regular rate (federal FLSA). Some states require daily overtime.
Is 8:30 AM to 5:00 PM 8 hours?
Yes, with a 30-minute unpaid lunch. Without lunch, it's 8.5 hours.
Next Steps for Your Payroll
- Hours Calculator — Decimal hours
- Salary Calculator — Annual from hourly
- Date Calculator — Days between
- Days Between Dates Guide — Calendar math
- Salary to Hourly Guide — Full conversion
Last updated October 2026. Verify overtime and lunch break rules with your state labor department.