Whole minutes first
A valid clock time becomes minutes after midnight: hours × 60 + minutes. Finish minus start gives the elapsed clock duration. Selecting “Ends next day” adds 1,440 minutes to the finish. Unpaid breaks are then subtracted.
Net minutes = finish minutes + next-day adjustment − start minutes − unpaid break minutes
Totals and decimal conversions
We add exact net minutes before converting the total to decimal hours. Three 20-minute entries total 60 minutes, not 0.99 hours. A decimal display is rounded only for presentation; the CSV includes exact minutes and four decimal places.
Reverse conversion multiplies decimal hours by 60 and rounds to the nearest whole minute; exact half-minute ties round up. This is not an employer’s rounding policy.
Optional gross earnings before tax
On work-hours, time-card, clock-out, decimal-hours and add-time tools, you can optionally enter an hourly rate and choose GBP (£), EUR (€) or USD ($). The estimate is calculated from exact worked minutes: worked minutes ÷ 60 × hourly rate. The result is rounded to the nearest minor currency unit (penny/cent); exact half-unit ties round up. The hourly rate accepts up to two decimal places and must be greater than zero.
The selected currency is the denomination of the rate and result. Changing GBP, EUR or USD does not convert the amount or fetch an exchange rate. The hourly rate is processed in this browser and is not included in optional saved time-card data. When earnings are enabled, the time-card CSV and print summary add a clearly labelled gross-before-tax estimate. This is not take-home pay: no tax, National Insurance, deductions, overtime premiums, holiday pay or other payroll rules are calculated.
Validation and limits
Impossible clocks, missing times, negative inputs, breaks longer than a shift and shifts longer than 24 hours are rejected. Equal start/finish is zero hours, or explicitly 24 hours with “Ends next day”. Time cards accept at most 100 rows over one or two weeks, and reject overlapping clock intervals, including overlaps crossing midnight.
The duration adder accepts up to 1,000 non-empty lines, four digits for each hour value and a combined total up to 1,000,000 minutes. It accepts durations, not pairs of start/finish clocks. The decimal converter accepts up to 10,000 hours and six decimal input places.
Week boundaries
Each shift belongs entirely to its starting day. A Sunday overnight shift is not divided between weeks. This convention is visible in the time-card explanation and export; check the convention required for your own records.
Important exclusions
No tool applies statutory or contractual overtime, break entitlements, tax, deductions, leave or payroll rounding. Dates, time zones, daylight-saving changes and attendance are not applied. Across a clock-change night, a clock-time difference can differ from actual elapsed time.
Report a discrepancy
Use Contact with a non-sensitive example. Include the start, finish, break and next-day choice, the result you expected, and the result displayed. Do not include another person’s payroll information.