Time Duration Calculator
A timesheet is arithmetic in base sixty, which is exactly where it goes wrong. Seven forty-five plus seven forty-five is fifteen thirty, not fourteen ninety — and the decimal version is 15.5 hours, not 15.3. People get the right total on a calculator and then write it down in the wrong notation. Both forms are given here, worked out from whole minutes rather than from each other.
What this generator does
Reads each line into a start, an end and an optional break, works out the length in whole minutes, and reports every entry and the total in both hours-and-minutes and decimal hours.
How to use this tool
- Write one line per entry: the start time, a dash, and the end time.
- Add a break in minutes after a comma, and a label after that.
- A shift that ends before it starts is treated as running past midnight.
- Read the total in hours and minutes, and in decimal hours.
Understanding the controls
- Your hours
- One line per entry. Times can be written 9:00, 09:00, 9.00 or 0900, and the dash can be a hyphen, an en dash or the word to.
- Break and label
- After the times, a break in minutes and then a label, separated by commas. Both are optional, and a break longer than the shift means the line is left out rather than counted as negative.
Common use cases
- Adding up a week's hours for a timesheet
- Working out billable time from a list of sessions
- Converting hours and minutes into the decimal hours a payroll system wants
- Checking a shift total that includes a night shift
- Totalling volunteer or contractor hours
How this generator works
Every figure is held as whole minutes, so nothing is ever added in a mixture of notations. The check adds the entries up again from their own printed lengths, confirms the total matches, and then converts the printed total back to minutes — which is what catches a total shown as fifteen point three when it should be fifteen and a half.
Randomness and fairness
Nothing is random. The same lines always give the same total.
For how randomness is produced across the whole site, see how Generate Random works.
Limitations and good to know
- Times only, with no dates: a shift ending before it starts is assumed to have run past midnight, which is right for a night shift and wrong for a two-day gap.
- Whole minutes, so seconds are not carried.
- One break per entry, given as a number of minutes rather than as its own times.
- No rounding rules for payroll, which vary by employer and are not applied.
Privacy and your data
Your hours stay in your browser. Nothing you type is transmitted or stored.
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