Timezone Converter
Enter a timestamp or date and see it converted across multiple timezones at once.
Understanding Timezones and UTC Offsets
A timezone defines the relationship between local time and UTC (Coordinated Universal Time). Most timezones are a fixed number of hours and sometimes minutes offset from UTC. Timezones that observe Daylight Saving Time (DST) shift their UTC offset by +1 hour during summer months, adding complexity to any date/time calculation.
Unix timestamps sidestep all of this: they are always in UTC and never change when clocks are adjusted. The conversion to local time happens only when displaying the timestamp — this is the correct architectural pattern for any application that stores or processes dates.
Major Timezone Offsets
| UTC Offset | IANA Identifier | Region / Notes |
|---|---|---|
| UTC−8 / −7 | America/Los_Angeles | Pacific Time (PST/PDT) — uses DST |
| UTC−5 / −4 | America/New_York | Eastern Time (EST/EDT) — uses DST |
| UTC+0 | Europe/London | GMT / BST — uses DST |
| UTC+1 / +2 | Europe/Paris | Central European Time (CET/CEST) — uses DST |
| UTC+3 | Asia/Riyadh | Arabia Standard Time — no DST |
| UTC+5:30 | Asia/Kolkata | India Standard Time — no DST |
| UTC+8 | Asia/Shanghai | China Standard Time — no DST |
| UTC+9 | Asia/Tokyo | Japan Standard Time — no DST |
| UTC+10 / +11 | Australia/Sydney | AEST/AEDT — uses DST (opposite hemisphere) |
DST Transitions — 2025
United States
Spring forward: Mar 9, 02:00 local
Fall back: Nov 2, 02:00 local
European Union
Spring forward: Mar 30, 01:00 UTC
Fall back: Oct 26, 01:00 UTC
Australia (eastern)
Spring forward: Oct 5, 02:00 local
Fall back: Apr 6, 03:00 local
United Kingdom
Spring forward: Mar 30, 01:00 UTC
Fall back: Oct 26, 01:00 UTC
Frequently Asked Questions
What is UTC and why is it important for timestamps?▼
UTC is the universal time standard for computing. Unix timestamps are defined as seconds since the Unix Epoch in UTC. Using UTC ensures timestamps are unambiguous regardless of where the server or user is located. Always convert to local time only for display.
What is the difference between a timezone and a UTC offset?▼
A UTC offset (e.g. UTC+5:30) is a fixed number. A timezone (e.g. America/New_York) includes rules for DST transitions, meaning its offset changes throughout the year. Always use timezone identifiers (IANA names) in code, not raw offsets.
How do I convert between two timezones in code?▼
Convert both times to UTC timestamps, then format each using the target timezone. In Python: datetime.fromtimestamp(ts, tz=ZoneInfo("America/New_York")). In JavaScript: new Intl.DateTimeFormat("en-US", {timeZone: "America/New_York"}).format(new Date(ts * 1000)).
Why do some UTC offsets have 30-minute increments?▼
Most timezones are whole-hour offsets, but a few countries chose half-hour or 45-minute offsets for geographic or political reasons. Examples: India (UTC+5:30), Nepal (UTC+5:45), Iran (UTC+3:30), Afghanistan (UTC+4:30), and Australia's Northern Territory (UTC+9:30).
Which timezone is best to store data in?▼
Always store in UTC (Unix timestamp or TIMESTAMP WITH TIME ZONE). Never store in local time. Convert to local time at the presentation layer using the user's timezone preference.