Time Calculator
Add or subtract two durations given in hours and minutes to get a normalized total.
How It's Calculated
Formula
\text{totalMinutes} = (\text{hoursA} \times 60 + \text{minutesA}) \pm (\text{hoursB} \times 60 + \text{minutesB})This calculator adds or subtracts two durations, each entered as whole hours and minutes (0-59). It is duration arithmetic, not elapsed clock-time between two timestamps: there is no start/end time, no calendar date, and no 24-hour wraparound. Each duration is first converted to a total minute count, then the operation is applied. For addition, the two minute totals are simply summed. For subtraction, duration B's minutes are subtracted from duration A's; a subtraction that would produce a negative duration is reported as a validation error rather than a signed or clamped result. The final minute total is then normalized back into whole hours plus remaining minutes (0-59), correctly carrying any overflow past 60 minutes into additional hours.
Worked Examples
Addition: 1h 45m + 2h 30m
- Duration A in minutes: 1 x 60 + 45 = 105.
- Duration B in minutes: 2 x 60 + 30 = 150.
- Sum: 105 + 150 = 255 minutes.
- Normalize: 255 / 60 = 4 hours remainder 15 minutes.
- Result: 4h 15m (255 total minutes).
Subtraction: 4h 15m - 2h 30m
- Duration A in minutes: 4 x 60 + 15 = 255.
- Duration B in minutes: 2 x 60 + 30 = 150.
- Difference: 255 - 150 = 105 minutes.
- Normalize: 105 / 60 = 1 hour remainder 45 minutes.
- Result: 1h 45m (105 total minutes).
Frequently Asked Questions
How is this different from the Hours Calculator?
Hours Calculator computes elapsed time between a start clock time and an end clock time, with an overnight toggle for crossing midnight. Time Calculator instead adds or subtracts two independent durations (hours + minutes) with no clock times or calendar involved at all.
What happens if I subtract a larger duration from a smaller one?
The calculator reports a validation error instead of returning a negative or signed duration. This V1 only supports unsigned duration arithmetic.
Can minutes be 60 or more in the input fields?
No. Each duration's minutes field must be between 0 and 59; carrying past 60 minutes into additional hours happens automatically in the result, not the input.
Are there any limits on how many hours I can enter?
Hours must be a non-negative whole number, but there is no upper limit — large hour values (for example, totaling hundreds of hours) are computed the same way as small ones.