Time Calculator
Add, subtract, multiply, or divide durations, or find the time between two dates.
Updates live as you type. A negative result (from subtracting a larger time) is shown with a leading minus sign. Runs entirely in your browser.
Need the opposite? Hours to Seconds Converter
What is Time Calculator?
Do duration math without reaching for a calculator: add or subtract two durations (hours, minutes, seconds), multiply or divide a single duration by a number, or find the elapsed time between two dates and times. Pick the operation from the dropdown and the result updates instantly. Results over 24 hours roll into a day count automatically, so a long total reads as, say, "2d 3h 15m 0s" rather than an unwieldy hour count. This covers the common duration-math cases developers and project planners run into: totaling work hours or video/audio clip lengths (add/subtract), scaling an estimate by a multiplier (multiply/divide), or measuring exactly how long between two timestamps (between two dates). Everything runs entirely in your browser; nothing you enter is sent to a server.
How to Use the Time Calculator
- 1
Pick an Operation: Choose Add, Subtract, Multiply, Divide, or Time Between Two Dates from the dropdown.
- 2
Fill in the Fields: Enter the duration(s) or date/time values the chosen operation needs.
- 3
Read the Result Instantly: The result updates automatically, with totals over 24 hours rolled into a day count.
Time Calculator Examples
Adding two durations: 2h 45m + 1h 30m = 4h 15m 0s. Multiplying a duration: 45m × 3 = 2h 15m 0s, useful for scaling a time estimate across multiple identical tasks. Time between two dates: from 2025-01-01 09:00 to 2025-01-03 17:00 is 2d 8h 0m 0s.
Frequently Asked Questions
Common questions about Time Calculator.