Convert GMT to UTC
UTC = GMT +0 h
GMT and UTC are the same time: both are UTC+0.
GMT · Greenwich Mean Time · UTC+0
12:14PM
Tuesday, November 3, 2026
UTC · Coordinated Universal Time · UTC+0
12:14PM
Tuesday, November 3, 2026
The UK is on GMT (UTC+0) right now.
- Next clock change: March 28, 2027. The UK moves to BST (UTC+1), so UTC is then 1 hour behind the UK.
- Next clock change: October 31, 2027. The UK moves to GMT (UTC+0), so the UK and UTC then read the same time.
GMT to UTC for every hour
Each hour reads the same on both sides, so this table only shows the two ways of writing it. The dot marks the current GMT hour.
| GMT | UTC +0 h | 24-hour |
|---|---|---|
| 12:00 AM | 12:00 AM | 00:00 → 00:00 |
| 1:00 AM | 1:00 AM | 01:00 → 01:00 |
| 2:00 AM | 2:00 AM | 02:00 → 02:00 |
| 3:00 AM | 3:00 AM | 03:00 → 03:00 |
| 4:00 AM | 4:00 AM | 04:00 → 04:00 |
| 5:00 AM | 5:00 AM | 05:00 → 05:00 |
| 6:00 AM | 6:00 AM | 06:00 → 06:00 |
| 7:00 AM | 7:00 AM | 07:00 → 07:00 |
| 8:00 AM | 8:00 AM | 08:00 → 08:00 |
| 9:00 AM | 9:00 AM | 09:00 → 09:00 |
| 10:00 AM | 10:00 AM | 10:00 → 10:00 |
| 11:00 AM | 11:00 AM | 11:00 → 11:00 |
| 12:00 PM | 12:00 PM | 12:00 → 12:00 |
| 1:00 PM | 1:00 PM | 13:00 → 13:00 |
| 2:00 PM | 2:00 PM | 14:00 → 14:00 |
| 3:00 PM | 3:00 PM | 15:00 → 15:00 |
| 4:00 PM | 4:00 PM | 16:00 → 16:00 |
| 5:00 PM | 5:00 PM | 17:00 → 17:00 |
| 6:00 PM | 6:00 PM | 18:00 → 18:00 |
| 7:00 PM | 7:00 PM | 19:00 → 19:00 |
| 8:00 PM | 8:00 PM | 20:00 → 20:00 |
| 9:00 PM | 9:00 PM | 21:00 → 21:00 |
| 10:00 PM | 10:00 PM | 22:00 → 22:00 |
| 11:00 PM | 11:00 PM | 23:00 → 23:00 |
GMT and UTC: the same clock, two names
There is nothing to convert: a time written in GMT and the same time written in UTC show the same digits. The two differ in what they are. UTC is the atomic time scale that every offset in the world is measured from. GMT is the older name for mean solar time at Greenwich, which today means UT1, a measure of how far the Earth has turned. Leap seconds have kept the two within 0.9 seconds of each other since 1972. Under CGPM Resolution 5 (2026), UTC becomes continuous on May 20, 2027, with the limit raised to one hour, so the difference can slowly grow.
The real trap: GMT in the UK in summer
The mistake that costs people a meeting is assuming “UK time” means GMT. The UK uses GMT only in winter. In summer the clocks there read BST, one hour ahead of UTC.
| From | London is on | London vs UTC |
|---|---|---|
| January 1 | GMT (UTC+0) | same time |
| March 28 | BST (UTC+1) | +1 h |
| October 31 | GMT (UTC+0) | same time |
So a time labelled “15:00 GMT” in July is still 15:00 UTC, but the clock on a London office wall says 4:00 PM. Check which one the writer meant. The UTC to London page gives the local reading for any date.
What GMT and UTC mean
Greenwich Mean Time
GMT is UTC+0. For conversions it equals UTC: the two have stayed within 0.9 seconds of each other, so they agree unless fractions of a second matter. The UK uses GMT only in winter; in summer it is on BST, UTC+1.
Coordinated Universal Time
UTC is the world’s reference time. It has no daylight saving time and no seasons: every UTC offset you see (UTC−5, UTC+5:30) is measured from it.