Convert Coordinated Universal Time to Greenwich Mean Time
Instantly convert Coordinated Universal Time (UTC) to Greenwich Mean Time (GMT) with our free online calculator.
Coordinated Universal Time
05:20:48 AM
Wed, Jun 24 (UTC)
Greenwich Mean Time
05:20:48 AM
Wed, Jun 24 (GMT)
Convert a Specific Time
24-Hour Comparison
| UTC | GMT |
|---|---|
| 12:00 AM | 12:00 AM |
| 1:00 AM | 1:00 AM |
| 2:00 AM | 2:00 AM |
| 3:00 AM | 3:00 AM |
| 4:00 AM | 4:00 AM |
| 5:00 AM | 5:00 AM |
| 6:00 AM | 6:00 AM |
| 7:00 AM | 7:00 AM |
| 8:00 AM | 8:00 AM |
| 9:00 AM | 9:00 AM |
| 10:00 AM | 10:00 AM |
| 11:00 AM | 11:00 AM |
| 12:00 PM | 12:00 PM |
| 1:00 PM | 1:00 PM |
| 2:00 PM | 2:00 PM |
| 3:00 PM | 3:00 PM |
| 4:00 PM | 4:00 PM |
| 5:00 PM | 5:00 PM |
| 6:00 PM | 6:00 PM |
| 7:00 PM | 7:00 PM |
| 8:00 PM | 8:00 PM |
| 9:00 PM | 9:00 PM |
| 10:00 PM | 10:00 PM |
| 11:00 PM | 11:00 PM |
How to Convert Coordinated Universal Time to Greenwich Mean Time
Formula
To convert Coordinated Universal Time (UTC) to Greenwich Mean Time (GMT): Convert UTC to GMT
About Coordinated Universal Time (UTC)
Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time, defined since 1972 as the time at the Prime Meridian (0° longitude) maintained by BIPM (Bureau International des Poids et Mesures) in Sèvres, France. UTC is computed as a weighted average of approximately 400 atomic clocks at ~80 national metrology institutes (NIST in the US, NPL in UK, PTB in Germany, NICT in Japan, KRISS in Korea, etc.) per the formal definition in ITU-R Recommendation TF.460-6 (2002). UTC is functionally identical to GMT (Greenwich Mean Time) for civil purposes but differs slightly in its underlying timescale — UTC uses atomic seconds with occasional leap seconds inserted (announced by IERS Bulletin C ~6 months in advance, last leap second was December 31, 2016, and the system may be retired by 2035 per Resolution D of CGPM 2022). UTC is the standard for aviation (ICAO Annex 5), maritime navigation (IMO COLREGS), all internet protocols (NTP, PTP per IEEE 1588), all scientific publications, GPS / Galileo / GLONASS / BeiDou GNSS, and Universal Time on Wikipedia/Wikidata.
About Greenwich Mean Time (GMT)
Greenwich Mean Time (GMT, IANA: Europe/London) is the historic and current civil time of the United Kingdom (during winter), Ireland (during winter), Portugal mainland (during winter), Iceland (year-round), and most West African countries. GMT is set at UTC+0 — the time on the Prime Meridian (0° longitude) running through the Royal Observatory in Greenwich, southeast London. Established as the global time reference by the 1884 International Meridian Conference in Washington DC, GMT served as the world's primary civil-time reference from 1884 until 1972 when UTC (Coordinated Universal Time) was adopted as the new precision standard. The UK switches from GMT to British Summer Time (BST = UTC+1) at 01:00 GMT on the last Sunday of March and back to GMT at 02:00 BST on the last Sunday of October per EU Directive 2000/84/EC (UK retained this schedule after Brexit). GMT affects: London Stock Exchange (LSE) trading hours, BBC World Service broadcast time-stamps, all aviation NOTAMs and weather METARs which use UTC = GMT, and ICAO + IMO worldwide maritime/aviation coordination.