How to Convert UK Time to UTC (and Back)
Converting UK time to UTC is easy once you know whether the UK is on GMT or BST. The rule is one line, but it is worth seeing examples.
The rule
In winter the UK is on GMT, so UK time and UTC are the same. In summer the UK is on BST, which is UTC+1, so subtract one hour from UK time to get UTC, and add one hour to UTC to get UK time.
Worked examples
15 January, 14:00 UK time is 14:00 UTC. 15 July, 14:00 UK time is 13:00 UTC. 15 July, 00:30 UK time is 23:30 UTC on 14 July, because subtracting an hour crosses midnight and changes the date.
Converting the other way, 09:00 UTC on 15 July is 10:00 UK time, and 09:00 UTC on 15 January is 09:00 UK time.
On the clock-change days
On the Sunday in March the clocks jump from 01:00 to 02:00, so there is no 01:30 UK time that day. On the Sunday in October the hour from 01:00 to 02:00 repeats, so 01:30 occurs twice: once at 00:30 UTC and again at 01:30 UTC. For anything critical, quote the UTC time as well.
Frequently asked questions
Is UK time the same as UTC?
In winter, yes. In summer UK time is one hour ahead of UTC.
Clock change guides
- What Is Daylight Saving Time (DST)? A Plain-English GuideWhat daylight saving time is, how it works in the UK, Europe and the US, why it exists, its history, who uses it and the argument over scrapping it.
- Why Do the Clocks Go Back in October? The Real ReasonThe clocks go back in autumn to return the UK to GMT, so winter mornings are lighter. The history, the rule, what time it happens and what changes for you.
- When Do the Clocks Go Forward Again After Going Back?When the UK clocks go forward again after the autumn change, how long the UK stays on GMT, when evenings get lighter and how to remember to reset your clocks.