Free time calculators
Ten calculators for the arithmetic that comes with tracking time: hours worked, time cards, timesheets, overtime, and the conversions payroll asks for. All of them are free, none of them need an account, and every one runs entirely in your browser, so nothing you type is sent anywhere.
Hours calculator
Time between two times across as many days as you need, with breaks and decimal hours.
Time zone converter
One time, every city you care about, with daylight saving applied for that date.
Time card calculator
A week of clock in and clock out times, with lunch deducted and overtime split out.
Work hours calculator
Working days and work hours between two dates, less holidays and leave.
Time duration calculator
How long between two times or dates, in days, hours, minutes and seconds.
Military time converter
24-hour to 12-hour time and back, with the full chart from 0000 to 2300.
Timesheet calculator
A week split across projects, with per-project totals and a billable figure.
Salary to hourly calculator
An annual salary as an hourly rate, and back, with weekly and monthly figures.
Minutes to decimal converter
Minutes to decimal hours for a timesheet, with a full 1 to 60 chart.
Overtime calculator
Time and a half and double time pay, with an adjustable threshold.
Meeting cost calculator
What a meeting costs in salary, live, while it runs.
Why a time tracking company builds calculators
Because the arithmetic is the easy half, and it is worth doing well and giving away. Working out that 09:00 to 17:30 less a 30 minute lunch is 8 hours, or 8.0 in decimal, takes a calculator. Working out where the other seven hours of a nine-hour day went takes a record.
Every tool on this page has the same limitation, and it is worth being direct about it: they can only add up what you remembered to write down. A timesheet filled in on Friday is a reconstruction of the week, and reconstruction is reliably smoother and more purposeful than the week actually was. The fragmented afternoons are exactly the ones that do not make it onto the sheet.
The other half
Cronus records which app and window you were in and works out what the time was in service of, automatically. There is no timer to start and nothing to write down, so the chaotic days produce a complete record rather than a gap in one.
$6 a month after a 21-day free trial. It never captures your screen.
The tracking side of this is covered in our explainer on AI time tracking: what it means, what each kind of tool can see, and how accurate it actually is.
Also worth reading: how to run a time audit, where the day actually goes, and working in 15 minute increments.