Timezone converter
Current time in two zones and the offset between them.
This runs in your browser. Nothing is uploaded.
About Timezone converter
Shows the current time in two time zones and the offset between them, calculated in your browser from the IANA database.
Scheduling across zones is a table people still do in their head, badly, especially around DST. I wanted two clocks and a sentence that says whether the other place is ahead or behind, without a world-clock product that wants a signup to save 'my cities'.
The zone lists come from the browser's IANA database when Intl.supportedValuesOf('timeZone') exists, with a short fallback list if it does not. Times are formatted with a short offset so you can see UTC+5:30 next to Asia/Kolkata instead of guessing. The offset line is the difference between those two offsets at this instant, which is what you want when asking 'is it too late to call'.
This is not a meeting planner. There is no 'find an overlap next Tuesday', no calendar invite, and no map. Those tools store your working hours. This one tells you what time it is there right now. The clocks tick once a second so you can watch a minute roll over; they are still just Intl.DateTimeFormat.
How to use Timezone converter
- 1Choose a from zone and a to zone.
- 2Read both current times and the offset between them.
- 3Change either zone; the clocks and the delta update.
What it won't do
- Current time only — no arbitrary date conversion.
- No meeting overlap chart and no saved cities.
Common questions
Does the timezone converter include daylight saving?
Yes, because it asks the browser for the offset at the current instant. When a zone is in DST, the short offset and the delta reflect that. It will not show you next October's offset unless you sit here until October.
Where does the list of time zones come from?
Intl.supportedValuesOf('timeZone') in browsers that have it, which is the IANA list the engine already ships. Older engines get a short built-in list of common zones. If a zone is missing, the engine is old, not the page being incomplete on purpose.
Can I convert a specific date and time, not 'now'?
Not on this page. A historical or future instant needs a datetime picker and a lot of honesty about what '9am in a zone that did not exist yet' means. I shipped the live pair of clocks first.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation