Time Calculator
Free time calculator. Add or subtract hours, minutes and seconds, or find the exact duration between two times in hours, minutes and seconds.
Time Inputs
Result
4h 15m 0s
Equivalents
How It Works
Pick a mode
Choose "Add / Subtract durations" to combine two time spans, or "Between two times" to measure a clock duration.
Enter the values
Type each duration in hours, minutes and seconds, or select a start time and end time on the clock.
See the result
The total is shown as hours, minutes and seconds, along with the equivalent in decimal hours, total minutes and total seconds.
A time calculator handles the arithmetic of hours, minutes and seconds, which is awkward to do by hand because time is base-60 rather than base-10. Whether you are combining the lengths of several tasks or working out how long an event lasted, doing it in seconds and converting back removes the risk of mis-carrying minutes.
This tool offers two modes. "Add / Subtract durations" combines two time spans and is ideal for stacking task lengths, lap times or media run-times. "Between two times" measures the gap between a start and end clock time, automatically rolling over midnight, which is perfect for shifts and schedules. Every result is also given in decimal hours, total minutes and total seconds for easy reuse.
Frequently Asked Questions
How does the calculator add two durations?
Each duration is converted into a single total of seconds, the two totals are added (or subtracted), and the result is normalized back into hours, minutes and seconds. This avoids the common mistake of carrying minutes and seconds incorrectly.
What happens if the result is negative?
When you subtract a larger duration from a smaller one the result is negative. The calculator keeps the sign and still shows a clean hours, minutes and seconds breakdown so you can see how far below zero the total is.
How is the duration between two times handled overnight?
If the end time is earlier than the start time, the calculator assumes the end time is on the next day and adds 24 hours. So a shift from 22:00 to 06:00 is correctly reported as 8 hours rather than a negative span.
What is a decimal hours value used for?
Decimal hours express a duration as a single number — for example 1 hour 30 minutes is 1.5 hours. It is the format most payroll, billing and spreadsheet systems expect, so it makes timesheets and invoices easier to fill in.
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