Time Add / Subtract Calculator
Add or subtract hours, minutes and seconds from a time of day.
Quick answer
- Formula: Result = (base time ± duration) modulo 24 hours; Days shift = whole days carried by the total
- Worked example — Resulting time (24h): 02:15:00 (full example below).
Time Add / Subtract Calculator
| Resulting time (24h) | 02:15:00 |
| Days shifted | 1 |
11:30 PM plus 2 hours 45 minutes is 02:15 the next day — a day shift of +1.
Add or subtract a duration from a time of day and get the resulting clock time. Results wrap around midnight, and the day shift tells you how many midnights were crossed in either direction.
Useful for working out arrival times, deadlines counted in hours, and schedules that roll into the next day — or back into the previous one.
The formula
Worked example
11:30 PM plus 2 hours 45 minutes is 02:15 the next day — a day shift of +1.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
What does a negative days shift mean?
Subtracting pushed the result into an earlier day. For example, 01:00 minus 2 hours is 23:00 with a day shift of −1: the previous day.
Can the amount be longer than a day?
Yes. Adding 50 hours to 10:00 gives 12:00 with a day shift of +2, because the total crossed two midnights.
Category: Date & Time calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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