How to calculate hours worked from a timesheet
Turn clock-in and clock-out times into paid hours: decimal hours, overnight shifts, breaks, weekly totals and the minimum wage check.
· Updated 12 October 2026 6 min read
Working out hours from a timesheet looks like primary school maths, yet it’s where a surprising amount of payroll error starts. The steps below work for paper timesheets, spreadsheets or exported clock data.
How do you calculate hours worked in a shift?
Take a 09:00 to 17:30 shift with a 30-minute unpaid lunch:
- Find the span. 09:00 to 17:30 is 8 hours 30 minutes.
- Subtract unpaid breaks. Take off 30 minutes, leaving 8 hours 0 minutes of paid time.
- Convert to decimal. 8 hours is 8.00. Multiply by the hourly rate for pay.
The easiest way to find the span is to convert both times to minutes after midnight. 09:00 is 540, 17:30 is 1,050. 1,050 minus 540 is 510 minutes, which is 8.5 hours.
Our timesheet calculator does all three steps, including the pay, in one go.
How do you convert minutes to decimal hours?
Payroll multiplies decimal hours by the rate, and minutes are not decimals. Divide the minutes by 60:
| Minutes | Decimal |
|---|---|
| 5 min | 0.08 |
| 10 min | 0.17 |
| 15 min | 0.25 |
| 20 min | 0.33 |
| 30 min | 0.50 |
| 40 min | 0.67 |
| 45 min | 0.75 |
| 50 min | 0.83 |
The classic error is treating “8.30” (meaning 8 hours 30 minutes) as 8.30 in decimal. That’s an 18-minute difference per shift: small once, real over a year across a team. The opposite error happens too: 7 hours 45 minutes typed as 7.45 underpays by 18 minutes.
A good habit is to keep the total in minutes until the very end, then divide by 60 once. Rounding each shift to two decimal places and then adding can leave the weekly total a minute or two out.
How do you calculate overnight shifts?
When the clock-out time is earlier than the clock-in, say 22:00 to 06:00, the shift has crossed midnight. Add 24 hours to the clock-out time before subtracting, so 06:00 becomes 30:00. 30:00 minus 22:00 is 8 hours before breaks, not minus 16.
Two other overnight details catch people out:
- Which day the hours belong to. Decide whether a shift counts on the day it starts or is split at midnight, and apply it consistently. It matters for weekly overtime thresholds and for any premium that applies to particular days.
- Clock changes. On the night the clocks go forward in March, a 22:00 to 06:00 shift is only 7 hours of real time. On the night they go back in October it is 9 hours. Pay what was actually worked.
How do breaks affect hours worked?
Only unpaid breaks are subtracted. If the contract pays breaks, leave them in paid hours.
For minimum wage checks, rest breaks are not counted as working time whether paid or unpaid, as GOV.UK’s guidance on working hours for which the minimum wage must be paid explains. Our guide to unpaid breaks and minimum wage walks through why.
Check the break was actually taken. A 30-minute break that’s deducted automatically, but was really spent covering the floor, is working time. Adult workers are entitled to a 20-minute break when they work more than 6 hours, under GOV.UK’s rest breaks guidance, so a timesheet that shows long shifts with no break is worth a second look. See UK rest break entitlement.
How do you add up a weekly timesheet?
- Work out each shift in minutes after breaks.
- Add the minutes for the week.
- Divide by 60 for decimal hours.
- Split out any hours paid at a different rate, such as overtime or a premium, and price each block separately.
Example week:
| Day | Shift | Unpaid break | Minutes worked |
|---|---|---|---|
| Mon | 08:45 to 17:15 | 30 | 480 |
| Tue | 09:00 to 17:20 | 30 | 470 |
| Wed | 12:00 to 20:40 | 45 | 475 |
| Thu | 22:00 to 06:00 | 30 | 450 |
| Fri | 09:00 to 13:00 | 0 | 240 |
| Total | 2,115 (35.25 hours) |
At £13.00 an hour, that’s 35.25 × £13.00 = £458.25. For how overtime is usually calculated, see how overtime pay works in the UK and the overtime calculator.
How do you check hours against the minimum wage?
Once you have hours and pay for the pay period, divide pay by hours. GOV.UK’s calculating the minimum wage guidance says to “divide the pay for the period by the number of hours worked in the period”, for a pay reference period of up to one calendar month. Compare the result with the current rate for the worker’s age: £12.71 an hour for workers aged 21 and over from April 2026.
Make sure “hours” means all working time, including time spent setting up before the rota start or closing down after clock-out. See do you have to pay staff for clocking in early?.
Where does the money leak?
Adding up paper or spreadsheet timesheets is slow, and it leaks money in predictable ways:
- Generous rounding. “Started about nine” becomes 09:00 on the dot every time. Rounding that only ever favours the employer is a minimum wage risk; rounding that only ever favours staff quietly inflates the wage bill.
- Forgotten breaks. An unpaid 30 left in the total is 30 minutes paid for nothing.
- Decimal slips. 7.45 typed for 7 hours 45 minutes.
- Missing clock-outs. A forgotten clock-out guessed at the end of the week.
- Buddy-punching. Someone clocking a colleague in. See how to stop buddy-punching.
How long should you keep timesheets?
Keep them: timesheets are your evidence that every worker was paid correctly. Our guide on how long to keep wage records covers the periods.
The faster way
WagePilot does the arithmetic for you: staff clock in and out on their phone with a geofence or QR check, or on a kiosk, the app subtracts unpaid breaks and totals approved hours, and you export the hours and pay estimates to your payroll. WagePilot is pre-payroll, so your payroll provider still runs the payslips.
FAQs
How do I calculate hours worked between two times?
Convert both times to minutes after midnight, subtract the start from the end, subtract unpaid breaks, then divide by 60.
What is 7 hours 45 minutes in decimal?
7.75 hours. Divide the 45 minutes by 60 to get 0.75.
How do I calculate a shift that goes past midnight?
Add 24 hours to the finish time, then subtract the start time. 22:00 to 06:00 becomes 22:00 to 30:00, which is 8 hours.
Should I round timesheet hours?
Recording exact minutes is safest. If you round, make sure it never leaves staff unpaid for time they actually worked.
This guide is general information, not legal advice. Check GOV.UK or a qualified adviser for your situation. WagePilot handles the tracking automatically, but you remain responsible for your own compliance.