Timezone converter
Converts time between timezones via a UTC reference. Shows the offset from the source zone and world clocks for 12+ cities.
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Timezone converter
Difference: —
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World clock
world clocks, refresh once per second03
About timezones
UTC — reference
UniversalUTC+0 = Greenwich · Coordinated Universal Time
UTC is Coordinated Universal Time, an atomic standard. All time zones are defined as offsets from UTC. Kept within 0.9 seconds of atomic clocks. In programming and aviation it's used as the single reference point.
DST — daylight saving
Not everywhereUS, EU — yes · RU, China, India — no
Daylight Saving Time shifts clocks forward by 1 hour for the summer. In effect in the US, Canada, EU, Australia. Russia abandoned it in 2011, China never used it. Because of DST, winter and summer offsets can differ: EDT (UTC-4) vs EST (UTC-5).
Non-round offsets
IST, NPTIndia: +5:30 · Nepal: +5:45 · Iran: +3:30
Not every zone is a whole hour. India (IST) — UTC+5:30, Nepal (NPT) — UTC+5:45, Iran (IRST) — UTC+3:30, parts of Australia — UTC+9:30. The reason is historical: countries chose an offset that matched sun time in the capital.
IANA names
DatabaseEurope/Moscow · America/New_York
The canonical timezone database is IANA Time Zone Database (tzdata). Format is 'Region/City'. Accounts for historical changes: DST rules, moves, abolitions. Updated several times per year. Used across Unix systems, JavaScript, Python and most databases.