CET sits at UTC+1, and GMT stays locked at UTC+0 all year. That makes the conversion permanent: add one hour, every time, no seasonal exceptions. The errors start when someone says "GMT" but means "whatever the clock says in London right now." In summer, London runs on BST (UTC+1), not GMT. If you schedule a July call for "14:00 GMT," you just booked it for 15:00 London time and 16:00 in Paris. That one-hour mistake is the most expensive typo in trans-European scheduling.
Add One Hour: The Only GMT to CET Rule You Need
GMT does not observe daylight saving time in 2026 or 2027. The offset stays UTC+0. CET is the standard time for Central Europe, fixed at UTC+1. No DST on the GMT side, no ambiguity. 09:00 GMT is 10:00 CET. 14:00 GMT is 15:00 CET. That is the entire formula.
When the UK is on GMT (late October to late March), London runs one hour behind Paris, Berlin, Madrid, and Rome. During that winter window, "UK local time" and GMT are the same thing. The confusion arrives with the spring clock change.
Does CET Observe Daylight Saving Time?
Central Europe switches to Central European Summer Time (CEST, UTC+2) from the last Sunday in March to the last Sunday in October. CET itself does not move. The conversion from GMT to CET stays add-one-hour, even in July. But in July, nobody in Paris or Berlin is on CET. They are on CEST.
So the practical question is not "GMT to CET" in summer. It is "GMT to CEST." That conversion is add two hours. The UK and Central Europe remain one hour apart all year (UK on BST at UTC+1, Europe on CEST at UTC+2), but the reference point matters. Say "14:00 GMT" in August and a Paris colleague hears 16:00 CEST. Say "14:00 London time" and they hear 15:00 CEST. Same gap, different anchor.
GMT to CET Conversion Table
| GMT (UTC+0) | CET (UTC+1) | CEST (UTC+2, late March to late October) |
|---|---|---|
| 00:00 | 01:00 | 02:00 |
| 06:00 | 07:00 | 08:00 |
| 09:00 | 10:00 | 11:00 |
| 12:00 | 13:00 | 14:00 |
| 15:00 | 16:00 | 17:00 |
| 18:00 | 19:00 | 20:00 |
| 21:00 | 22:00 | 23:00 |
Use the CET column when Europe is on standard time (late October to late March). Use the CEST column when Europe is on summer time. The GMT column never changes.
When Does Europe Switch Between CET and CEST?
Clocks go forward to CEST at 02:00 CET on the last Sunday in March. They fall back to CET at 03:00 CEST on the last Sunday in October. In 2026, those dates are 29 March and 25 October. For a call booked in the window between those dates, the relevant conversion from GMT is add two hours (to CEST), not one.
Why "GMT" Causes Scheduling Errors with Central Europe
The UK and Central Europe are always one hour apart. Winter: UK on GMT (UTC+0), Europe on CET (UTC+1). Summer: UK on BST (UTC+1), Europe on CEST (UTC+2). The gap never changes. What changes is what people call the time they are scheduling.
Someone in London says "let's talk at 14:00 GMT" in July. They mean 15:00 BST, their local time. The person in Berlin hears "14:00 GMT," converts to 16:00 CEST, and dials in an hour late. The fix: never say GMT when you mean UK local time. GMT is a fixed zone at UTC+0. UK local time is GMT only in winter. In summer, it is BST. If you mean London time, say London time. If you mean the fixed zone, say GMT and accept the consequences.
Travel agents and customer service teams are the worst offenders. They send confirmations reading "transfer at 09:00 GMT" for a July booking, when the actual pickup is 09:00 BST. That is a one-hour miss on the ground. State the local time of the location, or give both the local time and the fixed GMT offset. Do not mash them together.
Which Countries Use CET?
CET (UTC+1) is the standard time for Germany, France, Spain, Italy, Poland, the Netherlands, Belgium, Austria, Switzerland, Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Serbia, Bosnia and Herzegovina, North Macedonia, Albania, Kosovo, Malta, Liechtenstein, Monaco, San Marino, and Vatican City. Norway and Sweden use CET. Denmark uses CET. All switch to CEST (UTC+2) in summer.
Algeria and Tunisia use CET year-round with no DST. They stay at UTC+1 permanently, making the GMT to CET conversion add-one-hour in every season.
GMT to CET vs GMT to CEST: Which One Do You Actually Need?
Check the date. Between late October and late March, Central Europe is on CET. Use add one hour. Between late March and late October, Central Europe is on CEST. Use add two hours. If you are scheduling with Algeria or Tunisia, use add one hour regardless of the date.
For offsets beyond Europe, the full GMT offsets list covers every zone from GMT-12 to GMT+14.