How to Calculate Work Hours
Knowing exactly how many hours you’ve worked is essential for payroll, invoicing freelance clients, or tracking overtime. This guide explains the manual formula and shows you how to use a free calculator to do it instantly.
The Basic Formula
The core calculation is simple:
When working with hours and minutes, convert everything to decimal first: 30 min = 0.5 h, 45 min = 0.75 h.
Step-by-Step Calculation
- Record start and end times
Write down when you started and finished, including any shift changes or split shifts. - Subtract unpaid break time
Deduct all unpaid breaks (lunch, rest periods). Paid breaks are not deducted. - Convert to decimal hours
Minutes ÷ 60 = decimal. Example: 7h 45min = 7.75 h. - Sum across all workdays
Add daily totals to get your weekly or monthly total. - Identify overtime
Hours beyond 8/day or 40/week (varies by country) typically count as overtime.
Practical Example
A typical Monday–Friday work week:
| Day | Start | End | Break | Hours |
|---|---|---|---|---|
| Monday | 8:30 | 17:00 | 0.5h | 8.0h |
| Tuesday | 9:00 | 18:30 | 1.0h | 8.5h |
| Wednesday | 8:00 | 16:00 | 0.5h | 7.5h |
| Thursday | 9:00 | 17:30 | 1.0h | 7.5h |
| Friday | 8:30 | 16:30 | 0.5h | 7.5h |
| Weekly Total | 39.0h | |||
No overtime — just under the 40-hour threshold.
Calculate Work Hours Automatically
Instead of doing this manually, use our free Time Calculator. It handles multiple shifts, breaks, overnight hours, and even calculates overtime for you in seconds.
Open Time Calculator →Special Cases
Overnight Shifts
If you work past midnight, add 24 hours to the end time: 22:00 → 06:00 = (06:00 + 24h) − 22:00 = 8 hours.
Flexible and Remote Work
For remote workers, tracking small sessions throughout the day is common. Add each session individually, then sum. The Time Calculator’s “Sum multiple durations” mode is ideal for this.
Part-time and Variable Hours
For part-time workers or freelancers billing by the hour, multiply total hours by your hourly rate to get earnings: 23.5h × $35/h = $822.50.
Frequently Asked Questions
How do I calculate hours worked with a lunch break?
Subtract the break duration from your total time. If you work 8:00–17:00 with a 1-hour lunch break, your paid hours are 8 hours (9 total minus 1 break).
What is the formula for calculating work hours?
Work hours = (End time − Start time) − Break time. Convert times to decimal hours first: 30 minutes = 0.5 hours.
How do I calculate overtime?
Overtime is any hours worked beyond the standard threshold. In the US and many EU countries, this is 8 hours/day or 40 hours/week. Overtime pay is typically 1.5× or 2× the regular rate.
Can I calculate work hours across midnight?
Yes — add 24 hours to the end time if it is earlier than the start time. For example, a shift from 22:00 to 06:00 is 8 hours: (06:00 + 24:00) − 22:00 = 8 hours.