What this hours calculator does
This tool handles two everyday time questions. First: how much time passed between two clock times? That is the classic timesheet calculation — clock in, clock out, minus lunch — behind hourly payroll, freelance invoicing and shift planning. Second: what time will it be after adding or subtracting a chunk of time? Handy when a 9-hour shift starts at 10:30 pm and you need the exact end time.
Results appear in two formats at once: hours and minutes (7h 45m) for humans, and decimal hours (7.75 h) for spreadsheets, invoices and payroll software.
How to use it
- Pick a mode: Between two times to measure a duration, or Add or subtract time to shift a clock time forward or backward.
- In the first mode, set the start and end times. If the shift includes an unpaid lunch or other pauses, type the total minutes into Break to deduct (leave 0 if none).
- If the end time is earlier than the start time, the calculator treats the end as the next day and shows a notice — no extra setup for overnight shifts.
- Read the result as hours and minutes, and as decimal hours ready to multiply by an hourly rate.
- In the second mode, enter a base time, choose add or subtract, set the hours and minutes, and get the resulting time plus a note saying which day it lands on.
Turning minutes into decimal hours
Payroll systems and invoices work in decimal hours, not minutes. The conversion is one division: minutes ÷ 60. Fifteen minutes is 15 ÷ 60 = 0.25 hours, so a 7h 15m day is logged as 7.25 hours.
| Minutes | Decimal hours |
|---|---|
| 5 | 0.08 |
| 10 | 0.17 |
| 15 | 0.25 |
| 20 | 0.33 |
| 30 | 0.50 |
| 45 | 0.75 |
Values that do not divide evenly (10 or 20 minutes) are rounded to two decimals — accurate enough for most payroll, but agree on the rounding rule with your employer or client up front.
Worked example
A security guard works the night shift from 9:00 pm to 5:30 am with a 30-minute unpaid break.
- Since 5:30 am is earlier on the clock than 9:00 pm, the end time belongs to the next day. From 9:00 pm to midnight is 3 hours; from midnight to 5:30 am is 5 hours 30 minutes. Total: 8h 30m, or 510 minutes.
- Deduct the break: 510 − 30 = 480 minutes.
- That is 8h 0m of paid time.
- As a decimal: 480 ÷ 60 = 8.0 hours. At $12 per hour, the shift pays 8.0 × 12 = $96.
Overnight shifts without the headache
Shifts that cross midnight are where manual math usually goes wrong — subtracting the times directly gives a negative number. The rule here is simple: when the end time is earlier than the start time, add 24 hours to the end before subtracting. A 10:00 pm to 6:00 am shift is therefore 8 hours, and an amber notice confirms the entry was read as an overnight shift.
Frequently asked questions
How do I calculate my weekly hours?
Run each workday through the “Between two times” mode with its break deducted, then add up the decimal results: 8.0 + 7.75 + 8.5 + 8.0 + 7.75 = 40 hours flat. A weekly version that sums the days for you is on the roadmap.
What is 7.5 hours in hours and minutes?
7 hours and 30 minutes. Multiply the decimal part by 60 to get the minutes: 0.5 × 60 = 30. Likewise, 7.25 h is 7h 15m and 7.75 h is 7h 45m.
How is overtime paid?
It depends on your country’s labor law and your contract or collective agreement: thresholds and premium percentages vary widely. This calculator tells you exactly how many hours you worked — for the rate that applies to the extra ones, check your local labor law or ask payroll.
Can I deduct more than one break?
Yes. Add up the minutes of every unpaid pause and enter the total in the break field: a 30-minute lunch plus two 10-minute coffee breaks means 50 minutes to deduct.