Coordinated Universal Time (UTC) is the primary atomic time standard by which the world regulates clocks, telecommunications, financial markets, and aviation navigation.

What does UTC stand for?

UTC stands for Coordinated Universal Time. It was adopted in 1970 as a universal compromise between the English acronym CUT (Coordinated Universal Time) and the French acronym TUC (Temps Universel Coordonné).

Why is UTC used as the world's time standard?

UTC provides an unvarying, globally recognized benchmark regulated by ultra-precise international atomic clocks, eliminating regional ambiguities and national timekeeping discrepancies across global communications.

Does UTC change for daylight saving time?

No. UTC never observes daylight saving time and remains completely fixed year-round. All regional seasonal adjustments occur strictly within local civil time offsets.

What is a UTC offset?

A UTC offset is the positive or negative time difference between a local time zone and the zero meridian of UTC. For example, Central European Time is UTC+1, meaning it is one hour ahead of UTC.

How do I convert UTC to local time?

To convert UTC to your local time, add your regional offset if your location is east of Greenwich, or subtract your offset if you are west of Greenwich, adjusting for active daylight saving time if applicable.

What is the difference between UTC and GMT?

UTC is a scientific atomic standard governed by the International Bureau of Weights and Measures. Greenwich Mean Time (GMT) is a historic solar-based time zone centered on the Royal Observatory in Greenwich. While both share the same nominal time in winter, UTC is a standard rather than a civil time zone, and it never shifts for daylight saving.

什么是 UTC？世界协调时详解及 UTC 与 GMT 的区别

Coordinated Universal Time (UTC) is the primary time standard by which the entire world regulates clocks, aviation, telecommunications, financial markets, and internet infrastructure.

为什么它的英文简称是 UTC？

In 1970, the International Telecommunication Union sought a single global acronym. English speakers proposed CUT (Coordinated Universal Time), while French speakers proposed TUC (Temps Universel Coordonné). To avoid national bias, the compromise acronym UTC was formally adopted globally.

UTC 与 GMT 的区别对比指南

While UTC and Greenwich Mean Time (GMT) share the exact same nominal zero-hour time offset (UTC+0:00 / GMT+0), they are technically and historically distinct. In modern usage, UTC is a high-precision scientific standard, whereas GMT is a civil time zone and astronomical heritage system.

Attribute	UTC (Coordinated Universal Time)	GMT (Greenwich Mean Time)
Core Definition	Primary international time standard	Civil time zone & astronomical heritage baseline
Measurement Basis	International Atomic Time (TAI) from caesium atomic clocks	Mean solar time at the Royal Observatory in Greenwich
Daylight Saving (DST)	Never changes. Completely fixed year-round.	Shifts to British Summer Time (BST, UTC+1) during UK summer
Primary Application	Aviation, internet servers, space missions, financial markets	Civil time in the UK and parts of West Africa during winter
Governing Authority	International Bureau of Weights and Measures (BIPM)	UK national legislation & historical astronomical convention

民航 Zulu（祖鲁时 Z）与军事防御系统应用

In military operations, maritime navigation, and commercial aviation, UTC is universally designated as Zulu Time (abbreviated as Z). The letter 'Z' refers to the zero meridian of longitude. Because aviators cross dozens of time zones during international flights, all flight plans, air traffic control clearances, and aviation weather reports (METAR and TAF) are recorded strictly in Zulu time to eliminate catastrophic timezone conversion ambiguities.

计算机体系、数据库与Unix时间戳中的UTC基石

Software engineering and cloud infrastructure rely entirely on UTC as the canonical single source of truth. Distributed databases store event timestamps in standard ISO 8601 format (e.g. 2026-09-23T06:36:56Z) to avoid daylight saving time ambiguities. Furthermore, Unix epoch time counts the continuous number of non-leap seconds elapsed since January 1, 1970 00:00:00 UTC—inspect and calculate live epoch timestamps with our Unix Epoch Converter.

全球所有时区是如何以 UTC 为基准进行偏移换算的

Every regional timezone worldwide is defined as an offset relative to UTC, ranging from UTC-12:00 (Baker Island) to UTC+14:00 (Line Islands, Kiribati). Browse all national offsets in our Time Zones Directory, look up standard acronyms in our Abbreviations Glossary, or convert any offset in the Time Zone Converter.

Explore Related Time Standards & Tools

View current synchronized UTC time alongside all world cities, convert timestamps, or check DST transition dates.

Open World Clock → Convert Time Zones → DST Guide →

🌐 UTC Reference Guide

常见问题解答 (FAQ)

Authoritative answers to common questions about Coordinated Universal Time, atomic standards, and GMT differences.

什么是 UTC？

协调世界时（UTC）是全球用于规范时钟、电信网络、金融交易市场以及航空导航的核心原子时基准标准。

UTC 这几个字母代表什么？

UTC 代表“协调世界时”。1970年国际无线电咨询委员会为了兼顾英语缩写 CUT（Coordinated Universal Time）和法语缩写 TUC（Temps Universel Coordonné），折中确定为统一缩写 UTC。

为什么全世界都将 UTC 作为通用时间标准？

UTC 由全球数百台超高精度国际原子钟联合调控，提供恒定且公认的基准，消除了国际通信、航天和全球金融网络中的时差歧义与区域混乱。

UTC 会因夏令时而改变吗？

不会。UTC 全年恒定不变，永远不实行夏令时。任何季节性时钟调整完全发生在各个国家和地区的本地时间偏移层面上。

什么是 UTC 偏差量？

UTC偏移量是指当地时区与UTC零度经线之间的正负时间差。例如欧洲中部时间为 UTC+1，意为比协调世界时快1小时。

如何将 UTC 转换为本地时间？

若您位于格林尼治以东，将当地偏移量加到UTC时间上；若位于格林尼治以西则减去偏移量，并在夏令时期间加上1小时调整。

UTC 与 GMT 之间有什么区别？

UTC 是由国际度量衡局依据精密原子钟维护的科学时间基准。GMT 是以英国格林尼治天文台为基准的传统天文民用时区。冬季两者时间相同，但 UTC 是纯标准、永远不采用夏令时。