Free Date & Time Calculator

Add or subtract durations, or calculate the elapsed time between two clock times. See hours and minutes alongside decimal hours.

Add or subtract time

First duration hoursFirst duration minutesOperationSecond duration hoursSecond duration minutes

Choose durations and calculate.

Time between two clock times

Start timeEnd timeDays after start (0–365)Unpaid break (minutes)

For an overnight interval, set Days after start to 1.

Date and time difference

Compare calendar dates and local clock times. Each day counts as 24 hours; daylight-saving changes are not applied.

Start date and timeEnd date and time

Enter dates to calculate elapsed days, hours and minutes.

How to use this time calculator

For durations, enter hours and minutes separately. For clock times, select the start and end time and the number of calendar days between them. A start at 22:00 and end at 06:00 one day later gives 8 hours before breaks.

How do decimal hours work?

Divide minutes by 60. For example, 1 hour 30 minutes is 1.5 hours, not 1.30. The calculator rounds decimal-hour results to four places.

Can subtraction give a negative time?

Yes. Subtracting 3 hours from 2 hours gives −1 hour. Clock-time intervals must be nonnegative and breaks cannot exceed the interval.

Does it adjust for time zones or daylight saving?

No. This calculator uses local clock arithmetic without time-zone or daylight-saving changes. Use our Time Zone Converter for meeting planning across locations.