Time Calculator

Add and subtract time durations, shift a date and clock time forward or backward, or evaluate multi-term time expressions in one place.

Modify the values and click the Calculate button to use this tool.

Time Duration Calculator

Add or subtract two durations expressed in days, hours, minutes, and seconds.

Operation
Modify the values and click the Calculate button to use this tool.

Add or Subtract Time from a Date

Start from a calendar date and clock time, then add or subtract a duration to get the resulting date and time.

Operation
Modify the values and click the Calculate button to use this tool.

Time Expression Calculator

Evaluate a chain of time terms using d, h, m, and s units with + and − operators.

Use tokens like 1d, 2h, 30m, 45s separated by spaces. Example: 1d 2h + 4h 5s - 2030s

Related

Date Calculator Age Calculator Days Between Dates

Reference

1 day = 24 hours
1 hour = 60 minutes
1 minute = 60 seconds
Total seconds = ((d × 24 + h) × 60 + m) × 60 + s

How to use this time calculator

  1. Duration calculator: Enter two durations in days, hours, minutes, and seconds. Choose add or subtract and click Calculate to see the combined result in the result grid.
  2. Date & time shift: Set a start date and clock time (or click Now), choose add or subtract, enter a duration, and get the resulting date and time.
  3. Expression parser: Type a chain of time terms such as 1d 2h 3m + 4h 5s - 2030s to evaluate complex duration math in one step.

Time calculation formulas

Total seconds = ((days × 24 + hours) × 60 + minutes) × 60 + seconds

Durations are converted to total seconds, combined with addition or subtraction, then broken back into days, hours, minutes, and seconds. Borrowing is handled automatically so results stay in normalized form (for example, 90 minutes becomes 1 hour 30 minutes).

Example: 1 day 2 hours + 4 hours 5 seconds = 1 day, 6 hours, 0 minutes, 5 seconds.

Expression example: 1d 2h 3m 4s + 4h 5s − 2030s + 28h evaluates each token, applies operators left to right, and returns the total duration.

Real-world uses

  • Project tracking: Add logged work hours across multiple days to get total effort.
  • Event planning: Subtract setup time from a deadline to find when work must start.
  • Scheduling: Shift a meeting start time forward by a buffer duration.
  • Media & sports: Combine race segments, lap times, or playback durations.
  • Payroll & billing: Sum fractional hours and minutes for time-based charges.

Frequently Asked Questions

Enter each duration in the Duration 1 and Duration 2 grids using days, hours, minutes, and seconds. Select Add (+) and click Calculate. The result grid shows the combined total.

Yes. Choose Subtract (−) in the duration calculator. The first duration minus the second is computed. If the result would be negative, an error is shown instead.

Use tokens like 1d, 2h, 30m, and 45s with + and − operators between groups. Spaces separate tokens. Example: 1d 2h + 4h 5s - 2030s.

Yes. Enter the hour in 12-hour format (1–12), minutes, seconds, and select AM or PM. Click Now to fill in the current local date and time automatically.

The Time Calculator works with clock durations (hours, minutes, seconds) and can shift a specific date and time. The Date Calculator focuses on calendar dates — adding years, months, weeks, or days without clock-time precision.

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