Practical tools for measured work
Time zone converter
Convert dated local times between IANA zones with explicit daylight-saving ambiguity handling.
Calculate the layout, check the diagram, then print the result for the shop or jobsite.
For example America/New_York, Asia/Dubai or UTC.
This local time occurs twice. The selected earlier or later occurrence determines the result.
Clock changes in this calendar year
| UTC instant | Local time immediately before | Local time immediately after | Offset change (minutes) |
|---|---|---|---|
| 2024-03-10T07:00:00.000Z | 2024-03-10T01:59:59 | 2024-03-10T03:00:00 | 60 |
| 2024-11-03T06:00:00.000Z | 2024-11-03T01:59:59 | 2024-11-03T01:00:00 | -60 |
How it works
The geographic map marks representative IANA locations: blue for source and red for target. It shows locations, not legal time-zone boundaries. UTC has no geographic location. Zone names without a mapped representative point still convert normally.
Map: Natural Earth public-domain land · Locations: IANA time-zone database
Clock-change schedules use the source zone and the year of your entered date, from 1970 through 2100. The table shows both sides of each detected offset change. Select the relevant year rather than assuming every country changes clocks.
Enter the source wall-clock date and time and two IANA zone names. The converter finds matching instants using the browser’s time-zone rules. It rejects skipped local times and lets you choose either occurrence of a repeated time.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Local date and time
- 2024-11-03T01:30
- Source IANA time zone
- America/New_York
- Target IANA time zone
- Europe/London
- Repeated time occurrence
- Earlier occurrence
Primary result: Target minus source clock offset: 4 hours.
Before using the result
- Check the selected mode, units and input values before using the result.
- Read the assumptions and rounding rules; compare the worked example with your intended calculation.
- A numerical result does not supply missing context or change the stated limitations.
Limitations
Time-zone rules come from your browser’s database and may lag recent government changes. Use full IANA names or UTC; abbreviations such as CST are ambiguous. Leap seconds are not represented.
Frequently asked questions
Why can one local time have two results?
When clocks move backward, some local times repeat. For New York on 3 November 2024, 01:30 occurs at both 05:30 UTC and 06:30 UTC. Choose the occurrence you intend.
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