Tips4 min read1 de março de 2026

UTC vs GMT: Qual é a diferença?

UTC e GMT são frequentemente usados de forma intercambiável, mas diferem tecnicamente.

UTC vs GMT: What Is the Difference?

GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) both refer to the time at the Prime Meridian (0° longitude). For most practical purposes, they are interchangeable. But technically, they differ.

GMT is a time zone

GMT is the time zone used in the United Kingdom during winter. It is based on the position of the Sun relative to the Royal Observatory in Greenwich, London.

UTC is a time standard

UTC is not a time zone. It is a scientific standard maintained by atomic clocks worldwide. It is the basis for all civil time zones.

Key differences

FeatureGMTUTC

TypeTime zoneTime standard

BasisEarth rotationAtomic clocks

PrecisionVaries slightlyExtremely precise

Leap secondsNot applicableApplied when needed

UsageUK winter time, aviationGlobal standard

When does the difference matter?

For everyday scheduling and time zone calculations, GMT and UTC are identical. The difference matters only in scientific, navigation, or broadcasting contexts where sub-second precision is required.

Common confusion

GMT does not have DST. When the UK enters daylight saving time, it switches to BST (British Summer Time, UTC+1), not "GMT+1."

UTC never changes. It is always the same, year-round.

Best practice

Use UTC as the reference point when coordinating across time zones. It avoids confusion about whether GMT includes daylight saving adjustments.

Check the [current UTC time](/) on our homepage.

All articles

WorldTime Blog