Time Duration Calculator
Free time duration calculator: work out the hours and minutes between a start and end time, minus an unpaid break, including overnight shifts.
Enter the times
Enter a start and end time and any unpaid break. If the end is earlier than the start, the calculator treats it as an overnight shift.
The duration is the time between start and end, minus the unpaid break.
How the duration is calculated
The calculator turns the start and end times into minutes, wraps past midnight when the end is earlier than the start, and subtracts the unpaid break. The result is shown as hours and minutes, decimal hours, and total minutes.
It is a quick one-off check. When you no longer want to retype start and end times, Sandtime.io records the duration as you work and adds it up across the week.
Duration questions
What happens if the end time is earlier than the start?
It treats it as an overnight shift and adds a day, so 22:00 to 06:00 is eight hours rather than a negative number. Nothing needs to be entered twice.
Is the unpaid break taken off the total?
It is subtracted from the total, because an unpaid break is time on site but not time worked. Set it to zero to see the raw span between the two clock times.
Why show decimal hours as well as hours and minutes?
Payroll systems and invoices multiply by a rate, and 7 hours 30 minutes has to become 7.5 before that arithmetic works. The decimal figure here is rounded to two places, which is what most payroll and invoicing formats expect.
Can it add up a whole week?
It covers one span at a time. For a full week of days, with overtime and pay, use the time card calculator, which totals each day and the week together.
Is anything saved when I close the page?
No. The calculation runs in your browser and nothing is sent or stored, so closing the page clears it. If the hours need to survive and reach an invoice, they belong in a time record rather than a calculator.
Track durations, not the clock
Sandtime.io records how long work takes as it happens and rolls it into daily and weekly totals. Free for unlimited users, without surveillance.