Convert between any two zones
Pick a pair. Every figure follows the current daylight-saving rule rather than assuming winter.
The abbreviations, and which ones lie
| Abbr | Means | Winter | Summer | Fixed? |
|---|---|---|---|---|
| PST | Pacific Time | UTC−8 | UTC−7 | no — shifts |
| EST | Eastern Time | UTC−5 | UTC−4 | no — shifts |
| CST | Central Time | UTC−6 | UTC−5 | no — shifts |
| MST | Mountain Time | UTC−7 | UTC−6 | no — shifts |
| GMT | Greenwich Mean Time | UTC+0 | UTC+1 | no — shifts |
| UTC | Coordinated Universal Time | UTC+0 | UTC+0 | yes |
| CET | Central European Time | UTC+1 | UTC+2 | no — shifts |
| IST | India Standard Time | UTC+5:30 | UTC+5:30 | yes |
| JST | Japan Standard Time | UTC+9 | UTC+9 | yes |
| AEST | Australian Eastern Time | UTC+11 | UTC+10 | no — shifts |
| NZST | New Zealand Time | UTC+13 | UTC+12 | no — shifts |
| SGT | Singapore Time | UTC+8 | UTC+8 | yes |
| GST | Gulf Standard Time | UTC+4 | UTC+4 | yes |
Winter and summer figures are computed from the zone rules, for January and July respectively. Anything marked "shifts" is a zone whose offset you cannot state as a single number — which is most of them, and the reason so many scheduling errors happen.
The two dangerous abbreviations
IST means India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). Three different places, one abbreviation, up to four and a half hours apart. CST means US Central Time (UTC−6) and China Standard Time (UTC+8) — a fourteen-hour gap. If either appears in an email without a city attached, ask.
Questions
Which IST does this use?
India Standard Time, UTC+5:30. The abbreviation is genuinely ambiguous — it is also Irish Standard Time and Israel Standard Time — and every converter has to pick one. The overwhelming majority of searches for IST mean India, so that is the default, and it is stated on the page rather than left for you to discover the hard way.
And CST?
US Central Time, UTC−6 in winter. CST also means China Standard Time at UTC+8, which is a fourteen-hour difference from the one we default to — a mistake worth catching. If you want China, use the Shanghai row in the planner.
Why do the offsets change through the year?
Daylight saving. Most of North America and Europe shift by an hour twice a year, and the southern hemisphere shifts in the opposite months. Only a handful of the abbreviations on this page describe a fixed offset — UTC, JST, SGT and GST among them. The rest describe whichever half of the year you are in.
Is GMT the same as UTC?
For practical scheduling, near enough — they differ by well under a second. But GMT is often used loosely to mean 'UK time', and UK time is UTC+1 for half the year. If you need a reference that never moves, say UTC and mean it.
