Time Calculator
Add, subtract, multiply, or divide time durations expressed in d:h:m:s.
Inputs
Enter as d:h:m:s, h:m:s or m:s. Days are optional.
Used for Add and Subtract operations.
Result
03:45:00
Displayed as d:h:m:s or h:m:s.
Total Seconds
13,500
Total Minutes
225.0000
Total Hours
3.7500
Step by step
Duration A
= 02:30:00
Duration B (added)
= 01:15:00
Sum
02:30:00 + 01:15:00
= 03:45:00
In total hours
= 3.7500 h
How it works
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
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.