The week’s hours,
added up properly.

A worked example, using the defaults

Take the week the page opens with: nine hours on site Monday to Thursday, seven and a half on Friday, a half-hour unpaid break each day, weekend off.

Each of the four full days is nine hours on site less thirty minutes, so 8.5 hours. Friday is seven and a half less thirty minutes, 7 hours. The week is 34 + 7, 41 hours. Against a 40-hour threshold that is 40 hours at the basic rate and 1 hour of overtime. At time and a half on a rate of £18 an hour, the week pays 40 × £18 plus 1 × £27, which is £747. Pull Friday up to nine hours and the overtime becomes 2.5; drop the break to fifteen minutes and the week gains an hour and a quarter.

How to work out hours worked from a timesheet

Take the finish time away from the start time, in minutes, then take the unpaid break away from that. A day that runs 07:30 to 16:30 is 540 minutes; a 30-minute break makes it 510, which is 8.5 hours. Do that for each day, add the days, and you have the week. The mistake that catches most hand-written sheets is doing the arithmetic in hours and minutes as if they were decimals. 8 hours 45 minutes is 8.75, not 8.45, and a week of that error is the wrong side of two hours.

A night shift needs no special handling here. The slider carries the length of the shift rather than the clock face, so ten at night to six in the morning is eight hours like any other eight.

Breaks: paid, unpaid and the one the law requires

The calculator takes off only the break you set, because whether a break is paid is a matter for the contract, not for arithmetic. What the law requires is separate from what is paid. Regulation 12 of the Working Time Regulations 1998 entitles an adult worker to a rest break of at least 20 minutes in any day longer than six hours. The break is taken during the day, not at either end of it. If a day runs over six hours and the break is under 20 minutes, the tool says so. It does not say whether the break was paid, and it does not add one you did not take.

Overtime: daily, weekly, and what the law says about it

There is no statutory overtime rate in the UK. What counts as overtime and what it pays come from the contract. The two common shapes are a weekly threshold, hours above 37.5 or 40 in the week, and a daily one, hours above eight in any day. This tool uses the weekly threshold, because that is the shape most contracts take. Where yours counts by the day, the figure beside each slider is the day in front of you. The only legal floor is that average pay for all the hours worked must not fall below the National Minimum Wage or National Living Wage for the worker’s age.

The 48-hour week, and why an average is not a cap

Regulation 4 limits an adult worker’s working time to an average of 48 hours a week, over a reference period that is normally 17 weeks. That is unless the worker has signed an opt-out. A single week of 52 hours is not a breach on its own; a run of them is. The tool flags a week over 48 so you can look at the pattern. It also flags a day of more than 13 hours on site with the next day worked. Eleven clear hours of daily rest under regulation 10 will not fit around that unless the shift moved. Both are things to check, not findings.

Converting minutes to decimal hours

Divide the minutes by 60. Fifteen minutes is 0.25, thirty is 0.5, forty-five is 0.75, and ten minutes is 0.17 once rounded. Payroll systems and job costing both want decimals, which is why the results here show both forms: 8:45 for the person reading the sheet, 8.75 for the person keying it.

What this does not do

It does not know your contract, so it cannot tell you whether an hour is overtime, only whether it is above the threshold you set. It counts by the week, so a contract that pays overtime after eight hours in a day needs reading off the day figures yourself. It does not handle rest days, bank holiday premiums, shift allowances, travel time or a rota that changes mid-week. It moves in quarter hours, which is the unit a site timesheet is kept in and not the unit a clock is. Where the minute matters, take it from the sheet. And it keeps nothing: close the page and the week is gone, which is the point of a tool that promises not to send anything anywhere.

When the sheet is filled in by the gate instead

Every figure on this page was typed by somebody after the event, from memory or from a book in the cabin. That is the reason the arithmetic goes wrong, and it is the reason the week is argued about later. On a site running QR code clock-in the start and finish come from a scan at the poster, and the time is written by the server rather than the handset. The day line is already on the job at that person’s rate before anybody opens a spreadsheet on a Sunday. What an hour costs once the employer’s National Insurance and pension sit on top of it is on the savings calculator.

Not legal or payroll advice. The Working Time Regulations figures on this page are taken from the Working Time Regulations 1998 on legislation.gov.uk, regulations 4, 10 and 12, checked 7 September 2026. Overtime thresholds and rates are yours to set; the tool supplies none.