Local time → UTC
UTC = source local time − source offset
Example: 15:00 in Paris in September − (+2 h) = 13:00 UTC.
Time Zone Converter
Convert a local time between hundreds of IANA time zones (Europe/London, America/New_York, Asia/Tokyo…) with each country’s daylight-saving rules for the chosen date.
Enter a valid date, time and time zones.
Converted time
- From time zone
- To time zone
- ISO 8601
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How does this tool work?
What time is a 3 pm Paris video call in New York? When does a show broadcast at 8 pm in Tokyo start in London? This converter turns a local date and time in one time zone into the matching local time in another, using the real offset of each place on the chosen date: daylight saving time, standard time and non-whole-hour offsets (India, Nepal…). It shows the converted time in the target zone and the corresponding instant in Coordinated Universal Time (UTC) in ISO 8601 format.
A time zone is not a fixed offset but a history of rules. “Europe/London” is UTC+0 in winter and UTC+1 in summer, and these rules changed several times during the 20th century. The tool uses the identifiers of the IANA time zone database (tz database), the reference used by operating systems and browsers, as supplied by your browser through the Intl API.
Conversion happens in two steps: the time entered is first turned into a UTC instant using the offset of the source zone on that exact date, then that instant is displayed with the offset of the target zone. That is why the difference between two cities can change during the year.
Clock changes create two special cases. A time that does not exist (springing forward skips an hour) is moved forward by the length of the gap. A time that occurs twice (falling back repeats an hour) is read as the first occurrence, still on daylight time. These are the “compatible” rules of the JavaScript Temporal specification (TC39).
How to use this tool
Enter the date and time
Enter the date and time as shown on a clock in the source zone. The date matters: the offset can change from one week to the next.
Choose both time zones
Select the source and target zones by their IANA identifier, in the form Continent/City (Europe/London, America/Los_Angeles, Asia/Kolkata), or UTC.
Read the result
The converted time is shown with its date, which may be the day before or after, together with the UTC instant in ISO 8601 format.
How the conversion works
A zone’s offset depends on the instant: it is read from the IANA database for the date entered.
UTC → local time
target time = UTC + target offset
Example: 13:00 UTC + (−4 h) = 09:00 in New York.
- offset
- difference between local time and UTC at that instant, daylight time included (for example +02:00 or −04:00)
When the conversion crosses midnight the result shows it: 22:00 in Paris in winter is 06:00 the next day in Tokyo.
Use cases
International meetings
Announce a video call with each participant’s exact local time, including the weeks when Europe and North America have not yet changed their clocks together.
Travel and flights
Flight times are always given in local time: convert the arrival time to see what time it will be at home.
Live events
Product launch, match or concert announced in another country: get the matching time in your own zone.
Technical logs and UTC
Find the UTC instant of a local time (or the reverse by choosing UTC as the source) to compare server logs or timestamps.
Examples
Paris to New York in September
Paris is on UTC+2 and New York on UTC−4: a 6-hour difference.
Input
09/07/2026 15:00 · Europe/Paris → America/New_YorkResult
09/07/2026 09:00The out-of-step weeks in March
The United States moves to daylight time on 8 March 2026, the European Union only on 29 March: for those three weeks the gap is only 5 hours.
Input
03/20/2026 10:00 · Europe/Paris → America/New_YorkResult
03/20/2026 05:00A time that does not exist
At 2:00 French clocks jump straight to 3:00. The time entered is read as 3:30 summer time, i.e. 1:30 UTC.
Input
03/29/2026 02:30 · Europe/Paris → UTCResult
03/29/2026 01:30 UTCA quarter-hour offset
Nepal runs on UTC+5:45; India on UTC+5:30.
Input
06/01/2026 09:00 · Asia/Kathmandu → UTCResult
06/01/2026 03:15 UTCTips and best practices
- In the European Union and the UK, summer time starts on the last Sunday of March and ends on the last Sunday of October at 01:00 UTC everywhere at once; in the United States it runs from the second Sunday of March to the first Sunday of November at 2:00 local time.
- Southern-hemisphere countries (Australia, New Zealand, Chile…) put their clocks forward in the southern spring, around September–October, so their gap with Europe can vary by two hours over the year.
- Choose a city rather than an abbreviation such as CET or EST: abbreviations are ambiguous (IST can mean India, Ireland or Israel) and say nothing about daylight time.
- Rules still change (the Canadian province of Manitoba, for example, moves to UTC−5 all year round from 31 October 2026): an up-to-date browser ships the latest IANA database.
Sources and references
- IANA — Time Zone Database (opens in a new tab)Page in English
- IANA — Theory and pragmatics of the Time Zone Database (opens in a new tab)Page in English
- TC39 — ECMAScript Internationalization API (Intl) (opens in a new tab)Page in English
- TC39, Time Zones and Resolving Ambiguity (opens in a new tab), Temporal documentationPage in English
- Directive 2000/84/EC of the European Parliament and of the Council of 19 January 2001 on summer-time arrangements (opens in a new tab), Official Journal of the European Union, 2001Page in English
- 15 U.S. Code § 260a – Advancement of time or changeover dates (opens in a new tab), Legal Information Institute, Cornell Law SchoolPage in English
Frequently asked questions
Does the tool handle daylight saving time?
Yes. The offset applied is the one in force at the date and time entered, in each of the two zones. Just choose the right date.
What happens to a time skipped by the clock change?
It is moved forward by the length of the gap: 2:30 on 29 March 2026 in Paris becomes 3:30 summer time, the real instant at which a clock left behind would have been corrected.
And for a time that occurs twice in autumn?
The tool keeps the first occurrence, still on daylight time: 1:30 on 1 November 2026 in New York is 5:30 UTC. If you mean the second occurrence, add one hour to the result.
What is the difference between UTC and GMT?
For everyday use they show the same time. UTC is the international reference time scale; GMT historically means Greenwich Mean Time and today also names the UK’s winter time.
Why do some zones use half or quarter hours?
These are national choices: India is on UTC+5:30, Nepal on UTC+5:45, the Chatham Islands on UTC+12:45 (UTC+13:45 in the southern summer). The tool handles them like any other zone.
Is my data sent over the internet?
No. The conversion uses your browser’s time zone data and runs entirely on your device.
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