Time Calculator
Stack durations with per-row add/subtract, hours between clock times (overnight-aware) & unit conversion โ base-60 done right.
Tap the +/โ to flip a row between adding and subtracting. Values over 59 are fine โ 90 minutes works.
Total
4h 35m 30s
In minutes
275.5
In hours
4.59
In seconds
16,530
๐ก Time is base-60, which is why 2h 45m + 1h 50m isn't 3h 95m but 4h 35m โ the calculator carries minutes into hours the way clocks do.
โฐClock maths without the base-60 headache
Time refuses to be decimal: 2h 45m + 1h 50m is not 3h 95m. This calculator does the carrying for you in three modes โ add and subtract any number of durations (with per-row +/โ toggles for study-log corrections), hours between two clock times with an overnight option for night shifts and late-night study, and unit conversion between seconds, minutes, hours, and days.
๐Everything you'd want to know
- Stack up to 10 durations, each individually set to add or subtract โ perfect for totalling a study log minus breaks.
- Results in h/m/s plus decimal minutes, hours, and seconds for timesheets.
- Clock-time gaps with a crosses-midnight toggle โ 22:00 to 06:00 handled correctly.
- Overflow-friendly inputs: type 90 minutes and it normalises.
๐งฎThe maths
Converting to seconds first turns clock arithmetic into ordinary arithmetic โ the same trick used for the between-times mode, where an overnight span simply adds 24 hours before the subtraction.
๐กHandy time facts
- 0.5 hours is 30 minutes โ but 1.5 hours on a timesheet is 1h 30m, not 1h 50m; the decimal tiles avoid that trap.
- A day has 86,400 seconds โ memorising it speeds up every conversion.
- For dates rather than clock times, use our Date Calculator; for a per-day study budget, the Study Hours Calculator.
๐ก Frequently Asked Questions
How do I add hours and minutes together?+
Convert everything to a common unit, add, then normalise: 2h 45m + 1h 50m = 165 + 110 minutes = 275 minutes = 4h 35m. The calculator does the carrying automatically for any number of rows.
How many hours are between two times?+
Subtract start from end as minutes-since-midnight. 09:15 to 17:40 is 8h 25m. If the span crosses midnight (22:00 to 06:00), tick the overnight option and 24 hours are added before subtracting.
How do I convert minutes to hours and minutes?+
Divide by 60: the quotient is hours, the remainder minutes โ 150 minutes = 2h 30m. The convert mode also shows decimal hours (2.5) for timesheets.
Why is 1.5 hours not 1 hour 50 minutes?+
Because the decimal is a fraction of an hour: 0.5 ร 60 = 30 minutes, so 1.5 h = 1h 30m. The calculator shows both notations side by side to keep them straight.