Time Zone Difference Calculator
The local time somewhere else from a time here and the two UTC offsets, with the day shift.
Results
What this tool does
Scheduling across time zones goes wrong in two places: getting the sign of the offset backwards, and forgetting that the answer can land on a different calendar day. This does both explicitly — enter the offsets that apply on the date of the meeting, including summer time if it is in force, and the day shift tells you whether the other end is still on yesterday or already on tomorrow.
Formula
hour destination = (hour origin - time zone origin + time zone destination) mod 24
Variables
| Symbol | Meaning | Unit |
|---|---|---|
hh | Start hour | — |
mi | Start minute | — |
o1 | UTC offset here | h |
o2 | UTC offset there | h |
HD | Hour there | h |
MD | Minutes there | min |
DF | Time difference | h |
DY | Day shift | — |
UT | Time in UTC | h |
Worked example
- Start hour14
- Start minute0
- UTC offset here1 h
- UTC offset there-5 h
- Hour there8 h
- Minutes there0 min
- Time difference-6.00 h
- Day shift0
- Time in UTC13.00 h
Limitations
- Dates are handled as calendar dates. Time zones, daylight saving changes and public holidays are not taken into account.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
Frequently asked questions
Why do I have to enter the offsets myself?
Because offsets are political, not geographical, and they change. Daylight saving starts and ends on different dates in different hemispheres, several countries have abolished it recently, and a few use offsets that are not whole hours at all — India is +5:30 and Nepal +5:45. Entering the two offsets for the specific date you care about is the only way to be sure the answer is right.