Hours Between Two Times
Work hours, billable time, sleep duration — minus breaks if any.
For Time Sheets and Billing
The "decimal hours" field is the format most payroll and billing systems expect. Critical conversions:
| Clock Time | Decimal Hours |
|---|---|
| 8 h 15 min | 8.25 |
| 8 h 30 min | 8.50 |
| 8 h 45 min | 8.75 |
| 7 h 20 min | 7.33 |
| 7 h 40 min | 7.67 |
Don't enter raw clock time (8:30) into a decimal field — your hours will be 30% lower than intended. This is a common payroll error costing employees real money.
A 9 AM-5 PM shift isn't always 8 paid hours
Under U.S. Fair Labor Standards Act (FLSA) rules:
- Breaks under 20 minutes — must be paid (count as work time)
- Meal breaks 30 min+ — typically unpaid if employee is completely free of duties
- "Half-hour at desk eating while monitoring email" — must be paid (you're still working)
A standard 9-5 schedule with a 30-min unpaid lunch = 7.5 paid hours, not 8. Over a year (52 × 5 days), that's ~130 hours of unpaid time. State laws often add more protection — California, for example, requires paid 10-min breaks every 4 hours.
Crossing Midnight
If your end time is before your start time (e.g., 23:00 to 07:00), the calculator assumes you crossed midnight and adds 24 hours. Useful for overnight shifts, but verify if you have a split shift or multi-day calculation.
Time Format Standards
- 24-hour format (ISO 8601): 14:30 = 2:30 PM. Used by most of the world and all programming systems.
- 12-hour format (AM/PM): 2:30 PM. Used by most U.S. consumer-facing displays.
- Noon and midnight: Strictly speaking, "12 PM" is ambiguous; ISO 8601 uses 12:00 (noon) and 00:00 (midnight) to remove ambiguity.
Frequently Asked Questions
How do I add hours up across the day?
Convert each segment to decimal hours, then add. Or use the calculator multiple times and sum the results. The mistake to avoid: adding raw clock-time numbers (8:30 + 7:45 is not 16:15 — minutes don't carry like 100s).
What's "overtime" in the U.S.?
Federal FLSA defines overtime as hours over 40 in a workweek, paid at 1.5× regular rate. Some states have daily overtime (California: 1.5× after 8 hours/day, 2× after 12). Salaried employees above ~$43,888/year (2024) are typically exempt.
Do I round time?
Many timesheets round to the nearest 15 minutes (quarter-hour). Federal law (29 CFR § 785.48) allows rounding only if it doesn't systematically favor the employer. Common practice: round to nearest 0.25 hour for billing.