Timezone Converter — Compare World Clock Times Instantly
No time zones yet — add one above to start comparing.
Add the cities you care about and see their current time side by side, updating every second. Need to schedule a call? Pin a specific date and time in one zone and read off the matching time everywhere else — daylight saving is handled automatically.
How it works
- 1 Pick your source zone The tool starts in your own time zone with the live clock running. Use the source selector to change which zone the date and time fields represent.
- 2 Add the zones you want to compare Choose a city from the second dropdown and click Add. Each zone appears as a card showing its current time, date, and UTC offset.
- 3 Convert a specific time (optional) Edit the date or time field to pin a moment. Every card updates to the matching local time, with a badge when a city lands on the next or previous day. Click Now to return to the live clock.
Your data stays private
All processing happens entirely in your browser. No files, text, or data are ever sent to our servers. You can disconnect from the internet and this tool will still work.
Frequently asked questions
- Does it handle daylight saving time?
- Yes. Offsets are calculated for the exact date you enter using the browser's IANA time zone database, so spring-forward and fall-back transitions are applied correctly — including for past and future dates.
- Why does a city show +1 or -1 day?
- Time zones far east or west of your source can already be on the next calendar day, or still on the previous one, at the same instant. The day badge tells you when a converted time crosses midnight relative to your source zone.
- How many time zones can I add?
- As many as you like. Your selected zones and 12/24-hour preference are saved in your browser, so they're still there the next time you open the tool.
- What's the difference between UTC and GMT?
- For everyday purposes they're the same wall-clock time. UTC (Coordinated Universal Time) is the modern atomic-clock standard; GMT (Greenwich Mean Time) is the older astronomical one. This tool uses UTC offsets, so London reads UTC+00:00 in winter and UTC+01:00 during British Summer Time.
- Can I convert a time in the past or future?
- Yes. Set any date and time in the source fields and the conversion respects the DST rules that were (or will be) in effect on that date, not today's rules.
- Is my data sent anywhere?
- No. All time zone math runs in your browser using the built-in Intl API. Nothing you type is uploaded, and the tool keeps working offline once the page has loaded.