Date and Time Calculators

Hours Calculator

Add or subtract durations, convert decimal hours, or total multiple work shifts.

Combine hours and minutes or total multiple shifts with overnight and break support.

Calculate with the Hours Calculator

Dates are validated as calendar components before calculation.

Work shifts

An end time earlier than its start is treated as overnight.

How to use the Hours Calculator

  1. Enter the required calendar dates, times, or rule values.
  2. Choose the counting convention or mode where offered.
  3. Select Calculate or press Enter.
  4. Review the result, basis, and limitations before using it.

Worked example

2 h 30 min + 1 h 45 min = 4 h 15 min.

Assumptions

Date-only calculations use the proleptic Gregorian calendar and ignore clock time. Elapsed-time calculations and selected-zone conversions state their time basis separately.

Limitations

  • Each shift break must not exceed that shift.
  • Up to 50 dynamic shift rows are supported.

Frequently asked questions

What date basis does the Hours Calculator use?

The result uses calendar dates unless the page explicitly describes elapsed time or a selected time zone.

Can daylight-saving time change calendar-day totals?

No. Date-only calculations use normalized UTC day numbers. Elapsed timestamp and time-zone calculations are explicitly handled separately.

Are entered dates stored?

No. Calculations run in your browser and the entered dates are not saved or sent anywhere.