Hours Calculator: Calculate Hours Worked, Overtime & Payroll Time
The Hours Calculator above finds the exact number of hours between two clock times (with break deduction), or adds/subtracts hour-based durations — built specifically for timesheets, payroll, and billing, where getting the decimal conversion wrong means someone gets paid incorrectly.
How to Calculate Hours Worked
- Enter clock-in and clock-out times (e.g., 9:00 AM to 5:30 PM).
- Subtract any unpaid break using the Break field.
- Read the result in both HH:MM and decimal hours — decimal is what most payroll software needs.
Example: Clock in 9:00 AM, clock out 5:30 PM, 30-minute lunch break →
8 hours worked.
Decimal Hours vs. HH:MM — Where Payroll Errors Happen
$$\text{Decimal Hours} = \text{Hours} + \left( \frac{\text{Minutes}}{60} \right)$$
- Example: 7 hours 45 minutes is not 7.45 — it’s $7 + (45/60) = 7.75$ decimal hours.
- Why it matters: At $50/hour, entering “8.3” instead of 8.5 for “8 hours 30 minutes” underpays by $10. Our calculator outputs decimal hours automatically so this error can’t happen.
Handling Overnight & Across-Midnight Shifts
A shift from 10:00 PM to 6:00 AM can’t be calculated as simple subtraction (6 − 10 = −4). The calculator detects the wrap-around and correctly returns
8 hours.
Overtime Calculation
In the US, hours worked beyond 40 in a week typically require 1.5× pay. Add up your daily totals from the calculator across the week, then apply your overtime rate to anything over 40 — the decimal-hour output makes this arithmetic straightforward instead of error-prone.
Frequently Asked Questions
How do you add up hours and minutes?
Add hours and minutes separately, then carry over: if minutes reach 60 or more, subtract 60 from minutes and add 1 to hours. Example: 4h20m + 3h50m = 8h10m.
How many hours is 9 to 5?
8 hours. For any start/end time pair, enter both into the calculator above — it also handles breaks and overnight shifts automatically.
How do I calculate hours worked for payroll?
Enter clock-in and clock-out times, subtract any unpaid breaks, and use the decimal-hours output (not HH:MM) when entering totals into payroll or invoicing software.
How is overtime calculated from hours worked?
Total your weekly decimal hours first, then any hours beyond 40 (in the US) are typically paid at 1.5× the standard hourly rate.
What’s the difference between the Hours Calculator and Time Calculator?
This tool is built for work-hours use cases — timesheets, payroll, shift length, and overtime. For general date-independent duration math (adding/subtracting arbitrary time spans), use the
Time Calculator.
Real-World Use Cases
| Persona |
Input Strategy |
Key Benefit |
| Hourly Employee |
Clock In vs. Clock Out − Break |
Accurate paycheck-ready decimal hours. |
| Freelancer/Consultant |
Session start/end per client task |
Billable-hour accuracy for invoices. |
| Shift Worker |
Overnight clock-in/out |
Correct totals even across midnight. |
| Manager |
Weekly total vs. 40-hour threshold |
Quick overtime-pay calculation. |
