Gmt vs utc time code#
Gmt vs utc time iso#

You can see these calculations being made with Java code (not JavaScript as tagged on your Question) running live at. The time zone of Québec America/Montreal is five hours behind UTC at that moment, as noted by the -05:00.

That same simultaneous moment as seen on the clocks hanging on the walls in Québec show nearly 8 PM of the prior date: T19:55:31.820-05:00. The time zone of Tunisia Africa/Tunis is one hour ahead of UTC at that moment, as noted by the +01:00. That same simultaneous moment as seen on the clocks hanging on the wall in Tunisia show an hour later: T01:55:31.820+01:00. This is the time-of-day and date seen when standing before the clock displayed at the Royal Observatory Greenwich.

Your example of T00:55:31.820Z means an offset from UTC of zero hours-minutes seconds.

Gmt vs utc time iso#

Use this only when required for old protocols and systems not yet updated for ISO 8601. And they are bad for humans as they assume English language and particular cultural norms.Īvoid this format whenever possible. They are terrible, difficult to parse by machine. Your second example string Thu, 00:55:16 GMT is defined in the older standards RFC 1123 & RFC 822. The formats are wisely designed to be easy to parse by machine as well as easy to read by humans across cultures.Īlways choose ISO 8601 when serializing date-time values as text. The Z is pronounced 'Zulu' per military/aviation tradition. The Z on the end means UTC, that is, an offset-from-UTC of zero hours-minutes-seconds.The T in the middle separates the year-month-day portion from the hour-minute-second portion.The format seen in your first example T00:55:31.820Z is defined by the ISO 8601 standard. If you work for NASA, or the GPS/Galileo navigation projects, then you’ll want to learn more. Most programmers can use the terms interchangeably. This is a complicated topic, so see the Wikipedia pages for the gory details if you really want to know.įor common business apps, there is no significant difference, literally less than a second’s difference. UTC and GMT are two slightly different ways of tracking time. Avoid the legacy format of RFC 1123 & 822: Thu, 00:55:16 GMT.