Duration inputs
Enter each duration in days, hours, minutes, and seconds.
Add time
Use days, hours, minutes, and seconds. Subtract can go negative.
Add durations, subtract durations, or find the duration between two times.
Time Calculator
Add durations, subtract durations, or calculate the duration between two clock times with copy-ready results.
How this calculator works
Use this time calculator for quick duration math: add time, subtract time, or compare two clock times. The result stays prominent while the inputs remain compact underneath for fast correction.
Duration mode supports overnight time ranges, so an end time earlier than the start time is treated as crossing midnight. Add and subtract modes are useful when you already know the amount of time you want to apply to a starting value. Invalid entries show validation text instead of a misleading zero result.
Practical examples
- Add several durations to total lesson time, cooking steps, practice segments, or media lengths.
- Subtract a break or delay from a planned block when you need the remaining duration.
- Compare two clock times when you need the elapsed time between a start and end.
- Check a planned shift, call, study block, or countdown length before copying the final duration into another note or tool.
Add, subtract, and duration modes
Add mode combines two durations; it does not apply a duration to a dated clock instant. Subtract mode removes one duration from another and can produce a negative result. Duration mode compares two unzoned 24-hour clock times and treats an earlier end time as the following day. It does not apply timezone or daylight-saving rules.
Notes and limitations
This calculator is intended for ordinary time math and planning. For payroll, legal, billing, or compliance records, verify the result against the system or rules that apply to that work.
Related calculators
For a focused start-time to end-time result, use the time duration calculator. For hours remaining until a specific date and time, use the hours until calculator. For calendar dates, use the date duration calculator to count days between dates or the date calculator to add and subtract days, weeks, months, or years.
For unit conversions, use the milliseconds converter. For shift-style totals, try the work hours calculator. For time zone date boundaries, use the time zone converter. For timing something live instead of calculating it ahead of time, open the stopwatch or a countdown timer.
FAQ
Does this replace a timesheet or billing system? No. It is a planning and checking tool for time math. Use the rules, records, or systems that apply to formal work, billing, payroll, tax, legal, or compliance needs.
Why does the duration cross midnight? If the end time is earlier than the start time, the calculator treats the end as the next day so late-night ranges can be checked without manual date math.