How to calculate overtime
Overtime is the difference between the hours you worked and the hours you were expected to work. The only tricky part is getting the expected hours right.
Step 1: find your weekly target
Your target is the hours you are contracted to work in a normal week. If your contract gives daily hours, multiply by your working days: 8 hours × 5 days = 40 hours. A part-time contract of 6 hours over 4 days is a 24-hour week.
Step 2: adjust it for days off
A week with a day off is not a normal week, and you shouldn’t be marked down for not working on a public holiday. Take each day off out of the target:
- A full day off — holiday, sick leave, a public holiday — removes a full day: 40 − 8 = 32 hours.
- A half day off removes half a day: 40 − 4 = 36 hours.
Step 3: add up the hours you worked
Add up each day’s hours. If you record times as hours and minutes, convert them to decimal hours first — divide the minutes by 60 — or use the decimal hours converter, because 8:45 + 8:30 is 17:15, not 16:75.
Step 4: subtract
Overtime = hours worked − target. A positive result is overtime; a negative one is time you owe.
Worked examples
| Week | Target | Worked | Result |
|---|---|---|---|
| Normal week | 40 h | 43.5 h | +3.5 h overtime |
| Public holiday on Monday | 32 h | 34 h | +2 h overtime |
| Half day off on Friday | 36 h | 35 h | −1 h owed |
| Part-time, 24 h contract | 24 h | 27.25 h | +3.25 h overtime |
Try your own week in the weekly overtime calculator.
Step 5: keep a running balance
A single week tells you little: a 45-hour week followed by a 35-hour one evens out. What matters for time off in lieu, flexitime or a conversation with your manager is the cumulative balance — every week’s overtime added together. If you started tracking partway through a job, begin the balance at whatever you already had.
How much overtime is too much?
There is no single answer, but a useful rule of thumb is to look at your average over the last month, not one week. Clockflux treats up to 12.5% above target — 40 to 45 hours on a standard week — as on track, and flags anything above that as a pattern worth noticing. Rules on maximum hours vary by country: in the European Union, for example, the Working Time Directive caps the average working week at 48 hours, including overtime.
Paid overtime vs time off
Whether extra hours are paid, paid at a premium, given back as time off, or simply expected depends on your contract and local law. Knowing your exact balance is the first step either way — and tracking your hours is how you know it.
Let an app keep the balance
Clockflux does every step above automatically: it knows your working days, takes days off out of the target, and keeps a running overtime balance with a chart of how it has moved — see overtime and work/life balance.