Calculate days, hours, minutes and seconds in one place. Build a multi-step duration, solve a typed time expression or find the clock time after an exact interval. Calculate time instantly Choose a mode. The result updates while you type. Add or subtract durations. Multiply or divide the running total by a number. Use d, h, m, s or ms. Supported operators: +, −, ×, ÷, *, / and parentheses. Clock mode wraps after midnight. For date, time-zone and DST calculations, use the specialized Date and Time Calculator. 2d 4h 30m + 8h 45m − 20m = 2d 12h 55m Duration results do not depend on a time zone. More precise time calculators The main calculator handles duration arithmetic. Use a specialized tool when the calculation depends on two clock times, a date, a time zone or a work schedule. Time Duration Calculator Find elapsed time between a start and end time, including overnight intervals. Time Difference Calculator Calculate the directional or absolute gap between two clock times. Add Time Calculator Add a duration to a specific date or time with rollover details. Subtract Time Calculator Subtract hours, minutes or seconds from a selected date or time. Elapsed Time Calculator Measure how much time passed between two moments. Date and Time Calculator Add or subtract years, months, weeks, days and clock time. Time to Decimal Calculator Convert hours and minutes into decimal hours and back. Time Unit Converter Convert seconds, minutes, hours, days, weeks, months and years. How to use the time calculator Use Duration Math for multi-row calculations, Expression for typed equations or Clock Time for midnight rollover. Enter the time values Use days, hours, minutes and seconds. Decimal values are accepted. Select each operation Add or subtract another duration, then multiply or divide the running total by a numeric factor. Read and reuse the result View the normalized duration, total units and complete equation, then copy, share or print it.

Common time calculations Load an example directly into the calculator, then change any value. Add hours and minutes Subtract a break Add multiple sessions Multiply a duration Divide time equally Duration time vs. clock time A duration measures an amount of time and can continue beyond 24 hours. A clock time identifies a position within a day and wraps after midnight. The amount remains 27 total hours, which is also 1 day and 3 hours. 3:00 AM next day Starting at midnight, adding 27 hours moves the clock through one full day and three additional hours. How time addition and subtraction work The calculator converts every duration to seconds, applies the operations, then converts the final value back into readable units. This prevents errors when a value crosses a unit boundary. Popular date and time tools Continue with a calculator built for the exact task you need. Date Calculator Add or subtract calendar units from a selected date. Days Between Dates Count calendar days between two dates with endpoint controls. Date From Today Calculator Find a future date using days, weeks, months or years. Countdown Calculator Count down to any future date and time. Time Card Calculator Total employee shifts, breaks and weekly work hours. See the current date in common formats, day number and week number. Time calculator FAQ How CalendarHours verifies the result Duration inputs are converted to seconds, processed in operation order and normalized only for display. Expression mode uses a purpose-built parser rather than executing typed code. Clock mode uses fixed-duration arithmetic and reports the number of day boundaries crossed. Reviewed: August 2, 2026. Page date shown in your browser: August 2, 2026 . Find another CalendarHours tool Search calculators, dates, holidays, time zones, calendars and store hours.