Time Zone Converter
Convert a specific date and time from one time zone to another, with daylight saving time handled automatically by your browser's built-in time-zone data.
Quick answer
To convert a time between zones, you need the source time, its time zone, and the target time zone. This tool uses the browser's built-in IANA time-zone database (via Intl) to compute the equivalent wall-clock time in the target zone, automatically accounting for each zone's UTC offset and daylight saving rules. For example, 9:00 AM in New York is 2:00 PM in London.
Formula & method
The converter interprets your entered date and time as a moment in the chosen source zone, converts it to a single absolute instant, then formats that instant in the target zone using Intl.DateTimeFormat with the IANA zone identifiers (such as America/New_York or Europe/London). Because Intl carries each zone's historical and current daylight-saving rules, conversions stay correct across DST changes — no manual offset math.
Examples
- Input
- 9:00 AM, America/New_York → Europe/London
- Result
- 2:00 PM
- Why
- London is normally 5 hours ahead of New York, so 9 AM Eastern is 2 PM in London on the same day.
- Input
- 6:00 PM, Asia/Seoul → UTC
- Result
- 9:00 AM UTC
- Why
- Korea Standard Time is UTC+9 with no daylight saving, so 6 PM in Seoul is 9 AM UTC.
- Input
- Los Angeles → New York in summer
- Result
- +3 hours
- Why
- Both observe daylight saving, so the 3-hour gap holds; the tool applies the correct rules for the chosen date automatically.
When to use this tool
- Scheduling a call or meeting with people in other countries.
- Working out the local time of a webinar, launch, or deadline given in another zone.
- Planning travel arrivals and departures across time zones.
Common mistakes
- Forgetting that the answer can fall on the previous or next day when zones are far apart.
- Assuming a fixed offset year-round; daylight saving shifts many zones by an hour for part of the year, which this tool handles.
- Mixing up city names that share a name in different regions — pick the correct IANA zone (e.g. America/New_York).
Frequently asked questions
Does it handle daylight saving time?
Yes. It uses the browser's IANA time-zone data, which includes daylight-saving rules, so conversions are correct for the specific date you enter, including around the spring and autumn clock changes.
Why is the converted time on a different day?
When two zones are many hours apart, a time in one zone can fall on the previous or next calendar day in the other. The tool shows the correct target date along with the time.
Which time zones are supported?
A curated list of common IANA zones covering major regions. Each is identified by its standard name like America/New_York or Asia/Tokyo so the result is unambiguous.
Is the conversion done on a server?
No. It runs entirely in your browser using the built-in Intl time-zone database, so nothing is uploaded and it works offline once loaded.
What is UTC?
Coordinated Universal Time is the global time standard that does not change for daylight saving. Time zones are defined as offsets from UTC, which makes it a useful common reference.
Why use IANA names instead of abbreviations like EST?
Abbreviations are ambiguous and don't capture daylight saving, while IANA names like America/New_York identify a region's full set of rules, giving accurate, year-round conversions.
Sources & references
External references open in a new tab. We are independent and not affiliated with these organizations.
- ✓ Free to use
- ✓ No sign-up required
- ✓ Runs entirely in your browser — nothing is uploaded.
- ✓ Formula and method shown above
Provided “as is” for general information only — results may be inaccurate, so verify before you rely on them. No warranty; use at your own risk.
Built and reviewed by HIFreeTools against the formula shown above and any authoritative references cited on this page. See our methodology and editorial standards.
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