Use the United Kingdom Time Calculator to convert a date and time between the UK and major international time zones. It automatically follows Greenwich Mean Time and British Summer Time rules for the selected date.
Convert UK and world time
Around daylight-saving transitions, some local times may be skipped or repeated. The calculator warns when an entered wall-clock time cannot be matched exactly.
How the United Kingdom Time Calculator works
Choose a date, enter a local time and select the source and destination time zones. The calculator converts the source wall-clock time into an exact instant, then formats that instant in the destination zone.
Time-zone rules are date-sensitive. A London-to-New York difference is not always the same number of hours because the UK and United States change their clocks on different dates.
GMT and British Summer Time
The UK uses Greenwich Mean Time during the winter. During British Summer Time, UK clocks are one hour ahead of GMT. In 2026 the clocks go forward on 29 March and go back on 25 October.
Common UK time differences
| Destination | Typical difference from UK | Why it can vary |
|---|---|---|
| India | UK +4:30 or +5:30 | India has no seasonal clock change |
| Dubai | UK +3 or +4 hours | Dubai stays on UTC+4 |
| New York | Usually UK −5 hours | Clock-change dates differ |
| Los Angeles | Usually UK −8 hours | Clock-change dates differ |
| Singapore | UK +7 or +8 hours | Singapore stays on UTC+8 |
| Sydney | Often UK +9 to +11 hours | Both locations change clocks in opposite seasons |
Example conversion
On 1 July 2026, 3:00pm in London is during British Summer Time. New York is then five hours behind London, so the converted time is 10:00am in New York on the same day.
Useful planning tips
- Always select the actual meeting or travel date, not only today’s date.
- Check whether the converted time falls on the previous or next calendar day.
- Use the named time zone rather than manually assuming a fixed GMT offset.
- For travel connections, confirm local departure and arrival times with the transport operator.
Official source
Related UK calculators
Frequently asked questions
Is UK time always GMT?
No. The UK uses GMT in winter and British Summer Time, which is GMT+1, during the summer period.
Does the calculator handle BST automatically?
Yes. It uses the selected date and the Europe/London time-zone rules.
Why does the UK–USA time difference sometimes change?
The UK and United States begin and end daylight saving on different dates.
Can I convert a world time back to UK time?
Yes. Select the international location as the source and United Kingdom — London as the destination.
What happens when the converted time crosses midnight?
The result displays the correct destination date and reports whether it is the previous day, same day or next day.
Important: Use official schedules for time-critical travel, legal deadlines and broadcasts.