Greenwich Mean Time (GMT) and Central European Time (CET) differ by exactly 1 hour — a small but significant gap that separates the UK from most of continental Europe. London is always 1 hour behind Paris, Berlin, Amsterdam, and Brussels, making the GMT/CET gap the defining timezone relationship for intra-European business.

The Persistent 1-Hour Gap

CET is UTC+1 and GMT is UTC+0, placing continental Europe 1 hour ahead of the UK. This 1-hour difference holds year-round because the UK and the EU transition to daylight saving time on exactly the same date: the last Sunday in March (spring forward) and the last Sunday in October (fall back). When London moves from GMT to BST (UTC+1), Paris simultaneously moves from CET to CEST (UTC+2). The gap between them stays at exactly 1 hour.

This consistency makes GMT/CET one of the most reliable timezone relationships in the world for recurring scheduling. A weekly London–Frankfurt call at 9 AM GMT (10 AM CET) never needs to be adjusted for seasonal clock changes.

Quick Conversion Reference

To convert GMT to CET, add 1 hour. To convert CET to GMT, subtract 1 hour. This formula works year-round.

Why Is the UK Not on CET?

The UK’s use of GMT (and BST in summer) rather than CET is a historical and political choice. The Greenwich meridian was established as the world’s prime meridian in 1884, and the UK has aligned its clocks to it since then. When the rest of continental Europe adopted UTC+1 as their standard time in the twentieth century, Britain retained its GMT-aligned timezone partly out of national identity and partly because the sunrise times at UK latitudes would be uncomfortably late if the country moved to UTC+1 permanently.

Portugal, despite being on the Iberian Peninsula and geographically at a similar longitude to the UK, also uses GMT in winter and WET (Western European Time) — identical to GMT — for the same historical reasons. Spain, by contrast, uses CET despite being geographically aligned with the UK, a legacy of aligning with Nazi Germany during World War II.

Scheduling UK and Continental Europe Together

With only a 1-hour gap, UK and continental European teams have near-complete business-hour overlap. The main scheduling consideration is respecting the different lunch break cultures: UK workers often take a brief lunch at their desks, while French and Spanish workers value longer lunch breaks from noon or 1 PM. Scheduling a London–Paris meeting from 1:00 to 1:30 PM will be fine for London but potentially disruptive for Paris.