UTC

UTC (Coordinated Universal Time) is the global reference time standard. Every other time zone in common use is defined as an offset from UTC — usually a whole number of hours, occasionally a half or quarter hour (India is UTC+5:30; Nepal is UTC+5:45). UTC itself does not observe daylight saving.

UTC is maintained by the International Bureau of Weights and Measures (BIPM) and the International Earth Rotation and Reference Systems Service (IERS). Its tick rate comes from a weighted average of atomic clocks in 80+ laboratories worldwide. Occasional leap seconds have been inserted (or, hypothetically, removed) to keep UTC within 0.9 seconds of solar time. As of 2026 leap seconds are scheduled for deprecation in 2035.

UTC is often confused with GMT(Greenwich Mean Time). For most practical purposes they’re identical — both represent the time at the Greenwich meridian without DST. The technical difference is that GMT is defined by Earth’s rotation (which is irregular) and UTC by atomic clocks (which are regular). When the UK is on summer time it observes BST (British Summer Time = UTC+1); GMT is then unused as a clock label even though the timezone name persists.

Convert between UTC and any of 28 major time zones with our timezone converter, which uses the browser’s IANA timezone database for DST-correct results.