Time Zone Converter
Every international call scheduling failure is the same three traps: the raw hour difference, the date rolling over, and daylight saving moving one city but not the other. Enter a date and time in one zone and this converter answers all three for the zone on the other end — the local wall-clock time, the signed difference including half-hours, and whether the result lands next day or the day before.
The zone list covers the world's business hubs from New York to Auckland, and your device's own zone appears first so the common case is one dropdown. Conversions use your browser's built-in IANA timezone database, so DST transitions are computed exactly — a July date and a January date between London and New York genuinely differ by an hour, and the converter knows it. Your pairing is remembered for the next call.
How to use
- Pick the from-zone (your device zone is listed first) and enter a date and time.
- Choose the to-zone - the local time, hour difference and date shift appear instantly.
- Share the meeting time with one tap; the pairing is remembered on this device.
Frequently asked questions
How do I convert time between two zones?
Take the wall-clock time in the first zone, find its UTC instant, then re-express that instant in the second zone's rules. The calculator does this using the browser's IANA database - the same one servers use - rather than fixed offsets, so the answer is right on the exact date you enter.
Why does the time difference between two cities change through the year?
Daylight saving: zones shift on different dates (US and Europe differ by weeks) and not all zones observe it at all. London-New York is 5 hours in January but 4 in midsummer for the gap weeks. DST is handled automatically here - enter the real meeting date and you get the real answer.
What about half-hour and 45-minute offsets?
India sits at UTC+5:30, Nepal at +5:45, and parts of Australia at +9:30 - all in the list, and the difference line shows the minutes when they matter. This is a common failure of quick mental math that a converter never makes.
Does this work offline?
Yes - everything runs locally in your browser using its built-in timezone data, with no network calls or accounts. Save it to your home screen and it keeps working on a plane, which is exactly when you need it.