Time Duration Calculator

Calculate the time between two times

The Time Duration Calculator works out exactly how much time passes between a start and end time, subtracts any break, and shows the result in hours and minutes plus decimal hours. It even handles overnight shifts where the end time is earlier than the start. It's perfect for timesheets, billing, and shift planning.

Why decimal hours matter

Payroll and invoicing systems usually need time in decimal hours, not hours and minutes. Eight hours and thirty minutes is 8.5 decimal hours, but 8 hours and 20 minutes is 8.33 — not 8.20. Converting in your head is error-prone, so the calculator shows both formats, ready to drop into a spreadsheet or invoice.

How to use it

1. Enter the start and end times.
2. Enter any break in minutes to subtract.
3. Read the duration in hours/minutes and decimal hours.

Overnight shifts

If your shift crosses midnight — say 22:00 to 06:00 — a naive subtraction gives a negative number. This calculator detects that and adds 24 hours so you get the correct 8-hour result. That makes it reliable for night shifts, on-call periods, and any duration that spans two days.

Common uses

Use	Why
Timesheets	Log exact worked hours minus breaks
Billing clients	Convert to decimal hours for invoices
Shift planning	Check shift lengths including overnight
Study/work sessions	Measure focused time

Tips

• Subtract unpaid breaks to get billable or paid hours.
• Use the decimal figure for payroll and invoicing.
• For multiple shifts, calculate each and add the decimal hours.

Private and free

All calculations run in your browser — nothing is uploaded. The tool is completely free with no sign-up.