Time Zone Calculator
Convert a time between any two world time zones, handling DST.
About Time Zone Calculator
Pick a real location rather than a raw UTC offset. The converter looks up each zone's offset for the date you chose, so a conversion in January and the same conversion in July correctly differ where daylight saving applies. The resolved UTC instant is shown so you can verify the result, and the converter tells you when a local time is skipped or repeated by a daylight-saving transition.
Formula
The local reading is resolved to a UTC instant using the source zone's offset for that exact date (from the IANA time-zone database), then that instant is rendered in the target zone using the target's offset for the same instant. Because offsets depend on the date, daylight saving is handled automatically.
- source offset
- Derived from the source IANA zone and the chosen date — not entered by the user
- target offset
- Derived from the target IANA zone at the resolved instant
- UTC instant
- The unambiguous point in time both readings refer to
Worked example
With the default values below, Time Zone Calculator returns Converted Time of 00:00 (GMT+5:30 +05:30). Change any input above and every figure here is recalculated in your browser.
Inputs used
- Date (YYYY-MM-DD)
- 2026-10-29
- Time (HH:MM, 24h)
- 14:30
- From Zoneone of Los Angeles (America/Los_Angeles), Denver (America/Denver), Chicago (America/Chicago), New York (America/New_York), Bogotá (America/Bogota), São Paulo (America/Sao_Paulo), UTC, London (Europe/London), Paris (Europe/Paris), Berlin (Europe/Berlin), Athens (Europe/Athens), Moscow (Europe/Moscow), Dubai (Asia/Dubai), Karachi (Asia/Karachi), Kolkata (Asia/Kolkata), Kathmandu (Asia/Kathmandu), Dhaka (Asia/Dhaka), Bangkok (Asia/Bangkok), Singapore (Asia/Singapore), Shanghai (Asia/Shanghai), Tokyo (Asia/Tokyo), Seoul (Asia/Seoul), Sydney (Australia/Sydney), Auckland (Pacific/Auckland), Honolulu (Pacific/Honolulu), Johannesburg (Africa/Johannesburg), Lagos (Africa/Lagos), Cairo (Africa/Cairo)
- New York (America/New_York)
- To Zoneone of Los Angeles (America/Los_Angeles), Denver (America/Denver), Chicago (America/Chicago), New York (America/New_York), Bogotá (America/Bogota), São Paulo (America/Sao_Paulo), UTC, London (Europe/London), Paris (Europe/Paris), Berlin (Europe/Berlin), Athens (Europe/Athens), Moscow (Europe/Moscow), Dubai (Asia/Dubai), Karachi (Asia/Karachi), Kolkata (Asia/Kolkata), Kathmandu (Asia/Kathmandu), Dhaka (Asia/Dhaka), Bangkok (Asia/Bangkok), Singapore (Asia/Singapore), Shanghai (Asia/Shanghai), Tokyo (Asia/Tokyo), Seoul (Asia/Seoul), Sydney (Australia/Sydney), Auckland (Pacific/Auckland), Honolulu (Pacific/Honolulu), Johannesburg (Africa/Johannesburg), Lagos (Africa/Lagos), Cairo (Africa/Cairo)
- Kolkata (Asia/Kolkata)
Results
- Converted Time
- 00:00 (GMT+5:30 +05:30)
- Day
- next day
- Zone Difference
- +9h 30m
- Offsets
- EDT -04:00 → GMT+5:30 +05:30
- Daylight Saving
- America/New_York: daylight saving · Asia/Kolkata: standard time
- UTC Instant
- 2026-10-29T18:30:00.000Z
Step by step
- 1Local reading in the source zone
- 2Offset in force on that date (from the IANA database)Daylight saving is active on this date in the source zone.
- 3Resolved UTC instant
- 4Rendered in the target zone= 00:00 — next dayStandard time is in force on this date in the target zone.
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Does this handle daylight saving time?
Yes, automatically. Zones are real IANA identifiers (for example America/New_York), and the offset is looked up for the date you enter, so you get EST or EDT as appropriate without choosing between them yourself.
Why do I have to enter a date?
Because a zone's offset depends on it. 14:30 in New York is UTC−05:00 in January and UTC−04:00 in July, so a converter without a date has to guess and will be wrong for part of the year.
What happens on the day the clocks change?
Both awkward cases are reported. When clocks spring forward, some local times never occur, and the converter says so and uses the instant just after the change. When clocks fall back, some local times occur twice, and the converter uses the first occurrence and tells you.
Does it need an internet connection?
No. The time-zone rules come from your browser and the server runtime's built-in IANA database, so no external service is contacted and no data about your conversion leaves the calculator.