Time Duration Calculator

Whether you are filling in a timesheet, checking a payslip, or working out billable hours for a client, manually adding up hours and minutes is fiddly and easy to get wrong. This calculator works out the exact duration between two times, converts it into decimal hours for payroll, and can calculate pay if you add an hourly rate.

How to use the time duration calculator

Enter your start time and end time using the time pickers, then add any unpaid break you took, such as a lunch break. If you want to see your pay for the shift, add your hourly rate too. The calculator automatically handles overnight shifts, so you do not need to work out the maths yourself if your shift crosses midnight.

How the calculation works

The calculator converts your start and end times into minutes since midnight, then subtracts the start from the end to get the total shift length. If the end time is earlier than the start time, it treats the shift as running overnight and adds a full 24 hours before subtracting. Any unpaid break is then deducted from the total, and the result is shown as hours and minutes, and as decimal hours for payroll purposes. If you enter an hourly rate, decimal hours are multiplied by that rate to give total pay.

Worked example

Say you start work at 09:00 and finish at 17:30, with a 30 minute unpaid lunch break. That is 8 hours 30 minutes between start and finish, minus the 30 minute break, giving a total of 8 hours 0 minutes, or 8.00 decimal hours. At an hourly rate of £12.50, that works out as 8 × £12.50 = £100.00 for the shift.

Common mistakes people make

A common mistake is forgetting to deduct unpaid breaks, which can overstate paid hours by 30 minutes or more per shift, adding up significantly across a working week or month. Another mistake is manually converting minutes into decimal hours incorrectly, such as treating 30 minutes as 0.3 hours instead of the correct 0.5, which throws off any pay calculation based on it. For overnight shifts, people sometimes calculate a negative duration by subtracting the times directly without accounting for the shift crossing midnight, which this calculator handles automatically.

Related calculators

Once you have your total hours, our overtime pay calculator can work out pay for any hours above your standard contracted hours. If you are paid an annual salary but want to know your effective hourly rate, try our salary to hourly calculator, and our minimum wage calculator checks your hourly pay against the current legal minimum. Freelancers setting their rates may also find our guide to working out a freelancer hourly rate useful.