How many time zones are there?
The answer is not 24 — and depending on what you count, it is 38, or about 350, or somewhere in between.
The short answer
38 distinct UTC offsets are currently in use, spanning UTC−12 to UTC+14 — a 26-hour range across a 24-hour day.
If you count rule sets rather than offsets, the IANA database defines roughly 350 zone identifiers, because places sharing an offset can have different daylight-saving rules.
Why not 24
Three separate reasons, each adding to the count.
Half- and quarter-hour offsets. India is UTC+5:30, Nepal UTC+5:45, Iran UTC+3:30, Myanmar UTC+6:30, Chatham Islands UTC+13:45. None of these fits a 24-slot model.
Offsets beyond ±12. Kiribati sits at UTC+14 and Samoa at UTC+13, both chosen so those countries share a calendar date with their trading partners rather than with the sun. That pushes the total span to 26 hours.
Daylight saving. A zone that changes its clocks occupies two different offsets at different times of year, so the number in use at any given moment is not the number in use across the year.
Three different counts, three different questions
| Count | What it measures |
|---|---|
| 24 | Idealised meridian bands. Not the real world |
| 38 | Distinct UTC offsets currently in use |
| ~350 | IANA zone identifiers — distinct rule sets |
| ~40 | Offsets in use at any single instant |
The 350 figure is the one that matters for software. America/New_York and
America/Toronto share every offset and every rule today, but they are separate
entries because they have not always agreed historically — and a database that
merged them would convert old timestamps wrongly.
Zones per country
Russia has the most: eleven, from UTC+3 in Kaliningrad to UTC+12 in Kamchatka.
France is often cited as second with twelve, counting its overseas territories across the Atlantic, Indian and Pacific oceans. The United States has six including Alaska and Hawaii, nine counting territories.
China has one, for a country geographically wide enough for five. India has one, for a country wide enough for two.
None of this follows from geography. It follows from politics.
The 26-hour spread in practice
Because offsets run from −12 to +14, there is a period of every day when three different calendar dates are in use somewhere on earth simultaneously.
For most of any given day, two dates coexist. That is why "tomorrow" is a genuinely ambiguous word across a wide gap, and why date-only deadlines are a bad idea internationally.
Related: UTC offsets: the full list · Why do time zones exist?
Timezone: World Clock Widget
A world clock, converter and live day/night map for iPhone — 325 cities, offline, no account.
Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.