Time Zone Converter
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Time Zone Converter
Every number is calculated in your browser. Nothing is sent to a server.
How it works
About this calculator
Pick a source zone and a time, then compare it across the cities that matter. Offsets, date rollovers and daylight-saving transitions all come from the IANA time zone database.
Real offsets
Offsets are calculated for the selected date, not fixed values — so summer and winter times are both correct.
Day rollover
When a city is already on the next or previous date, the row is marked so meetings are harder to miss.
Add your own cities
Use the selector under the list to add any IANA time zone; remove rows you do not need.
Questions & answers
Frequently asked
How is daylight saving handled?
The browser’s Intl API applies the IANA rules for the exact date you choose, including transitions that happen at 02:00 local time.
Can I compare more than four cities?
Yes. Add as many zones as you like from the selector; the list stays in your browser session.
Results are provided for convenience. For legal, payroll or medical decisions, confirm with a qualified professional.