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Hours Calculator

Add or subtract time durations instantly. Enter hours and minutes like 8:30 and 7:45 to get the total time, minutes and decimal hours — free timesheet helper.

About this tool

Adding hours and minutes by hand is where silly mistakes live: 8:30 plus 7:45 is not 15:75, it is 16:15. Anyone filling timesheets, totaling shift work, or adding up project hours has felt that friction. This calculator does the carrying for you.

Type two durations in H:MM format, pick add or subtract, and get the exact result — plus the total in minutes and in decimal hours, the format most payroll systems want.

How to use

Enter each duration as hours, a colon, and minutes — like 8:30 or 42:15. Hours may exceed 24, so weekly totals work fine; minutes must be 00 to 59. Choose Add or Subtract, then press Calculate.

The result shows H:MM first, then total minutes, then decimal hours (16:15 becomes 16.25 h), which you can copy straight into timesheets and invoices.

The math behind it

The math: convert each duration to minutes (hours × 60 + minutes), add or subtract the totals, then convert back by dividing into whole hours and leftover minutes. Decimal hours are simply total minutes ÷ 60.

Example: 8:30 is 510 minutes and 7:45 is 465 minutes. Added: 975 minutes = 16:15, or 16.25 hours. Subtracted: 45 minutes = 0:45.

Frequently asked questions

How do I add hours and minutes, like 8:30 + 7:45?
Convert both to minutes (8:30 = 510, 7:45 = 465), add them (975), then convert back: 975 minutes is 16 hours and 15 minutes. This calculator does all three steps instantly and also gives you the decimal-hours figure.
How do I subtract time, for example 8:30 minus 7:45?
Same idea in reverse: 510 minutes minus 465 minutes leaves 45 minutes, shown as 0:45. If the result goes negative — say 7:45 minus 8:30 — the tool shows it with a minus sign so nothing is hidden.
Can I add durations longer than 24 hours?
Yes. Hours are not capped at 24, so weekly shift totals like 38:20 + 4:10 = 42:30 work exactly as you would expect. Only the minutes part must stay between 00 and 59.
What format do I type the time in?
H:MM — hours, a colon, two-digit minutes. Examples: 8:30, 0:45, 125:00. Do not use decimals (8.5) or seconds; the tool validates the format and warns you if something is off.
How do I convert the result to decimal hours for payroll?
Divide the minutes by 60: 16:15 is 16 + 15/60 = 16.25 hours. The calculator prints this decimal figure under every result, ready to paste into payroll software or invoices.

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