Time Calculator
Add, subtract, multiply and divide time expressed in days, hours, minutes and seconds.
About Time Calculator
This calculator performs arithmetic on time durations. Add and subtract combine two durations and return the d:h:m:s result. Multiply and divide scale a single duration by a numeric factor — for example, doubling a 2h30m shift gives 5h00m. All operations work internally in seconds for precision, then convert back to the familiar d:h:m:s format for display.
Formulas
Addition / Subtraction
Result (s) = Duration A (s) ± Duration B (s)
- T_A
- Duration A in seconds
- T_B
- Duration B in seconds
Multiply / Divide
Result (s) = Duration A (s) × factor
- T_A
- Duration A in seconds
- k
- Numeric factor
Worked example
With the default values below, Time Calculator returns Result of 03:45:00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Operationone of Add (A + B), Subtract (A − B), Multiply (A × factor), Divide (A ÷ factor)
- Add (A + B)
- Duration A (d:h:m:s or h:m:s)
- 02:30:00
- Duration B (d:h:m:s or h:m:s)
- 01:15:00
- Factorminimum 0
- 2
Results
- ResultDisplayed as d:h:m:s or h:m:s.
- 03:45:00
- Total Seconds
- 13,500
- Total Minutes
- 225.0000
- Total Hours
- 3.7500
Step by step
- 1Duration A= 02:30:00
- 2Duration B (added)= 01:15:00
- 3Sum= 03:45:00
- 4In total hours= 3.7500 h
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What input format does the calculator accept?
Any of: d:h:m:s (e.g. 1:02:30:00), h:m:s (e.g. 02:30:00), or m:s (e.g. 90:00). Days are optional — omit them when the duration is under 24 hours.
Can the result be negative?
Yes. If you subtract a larger duration from a smaller one, the result is negative and is displayed with a leading minus sign.
What does multiplying a duration mean?
The entire duration is scaled by the factor. For example, multiplying 1h30m by 2 gives 3h00m. Fractional factors like 1.5 are supported.
How are hours and total hours different?
The 'Result' shows the duration in d:h:m:s format where hours resets to 0 each day. 'Total Hours' converts the entire duration to a decimal hour count.