Time difference calculator
Two places, one date: the exact gap between their clocks.
From: New York
To: London
London is
5 h ahead
of New York · EDT UTC−4 vs GMT+1 UTC+1
In 2026 the gap changes on March 8 (to 4 h ahead), March 29 (to 5 h ahead), October 25 (to 4 h ahead), November 1 (to 5 h ahead).
| New York | London |
|---|---|
| 8:00 AM | 1:00 PM |
| 9:00 AM | 2:00 PM |
| 10:00 AM | 3:00 PM |
| 12:00 PM | 5:00 PM |
| 2:00 PM | 7:00 PM |
| 4:00 PM | 9:00 PM |
| 5:00 PM | 10:00 PM |
| 6:00 PM | 11:00 PM |
See the gap move through the year
Place A: New York
Place B: London
Tue, March 17, 2026
Not the usual gap (5 h ahead). One place has changed its clocks and the other has not yet — a recurring meeting booked in one zone moves by an hour for the other.
Questions people ask
How is the time difference calculated?
For the date you choose, the calculator reads each place’s UTC offset from the IANA time zone database and subtracts one from the other. It is exact for that date, including daylight saving time and half-hour zones such as India (UTC+5:30) or Newfoundland.
Why is the difference different on another date?
If one place uses daylight saving time and the other does not, or they switch on different dates, the gap changes during the year. The calculator lists the dates when that happens for the year you picked.
What does “ahead” mean?
“London is 5 h ahead” means London clocks show a later time than New York clocks at the same moment — it is already 2 pm in London when it is 9 am in New York.