What Is a Time Zone Converter?
A time zone converter translates a time from one place to another. If it's 3 PM in London, what time is it in Tokyo? If you're scheduling a call between New York and Sydney, what time works for both? A time zone converter answers those questions instantly.
How to Use This Tool
- Set a reference time — pick the time, date, and time zone you want to convert from.
- Add cities — choose from 400+ cities and add them to the world clock list.
- See live updates — every clock updates in real time as seconds tick by.
- Compare at a glance — day/night indicators and the work-hour strip make planning easy.
- Copy all — click "Copy All" to grab a text version of the whole list.
How Time Zones Work
The world is divided into 24 time zones, each roughly 15° of longitude wide. The zones are referenced against UTC (Coordinated Universal Time) — the modern successor to GMT.
- UTC+0 — London (in winter), Reykjavik, Accra
- UTC+5:30 — India (a half-hour offset)
- UTC+5:45 — Nepal (a quarter-hour offset)
- UTC−5 — New York (in winter)
- UTC+9 — Tokyo, Seoul
- UTC+10 — Sydney (in winter)
Offsets aren't always whole hours — some regions use half-hour or quarter-hour offsets.
DST — Daylight Saving Time
Many countries shift their clocks forward by one hour in spring and back in autumn to make better use of daylight. This is called Daylight Saving Time (DST), or "summer time" in the UK and Europe.
- DST start — clocks go forward (lose an hour)
- DST end — clocks go back (gain an hour)
- Not universal — many countries don't observe DST, and start/end dates vary
- Southern Hemisphere — DST is offset by six months (their summer is our winter)
This tool uses the browser's built-in time zone database, which includes current DST rules. It automatically adjusts for DST based on the date you select.
Common Time Zone Abbreviations
- UTC — Coordinated Universal Time (the global reference)
- GMT — Greenwich Mean Time (functionally same as UTC)
- EST/EDT — Eastern Standard/Daylight Time (US East Coast)
- CST/CDT — Central Standard/Daylight Time (US Midwest)
- MST/MDT — Mountain Standard/Daylight Time (US Rockies)
- PST/PDT — Pacific Standard/Daylight Time (US West Coast)
- BST — British Summer Time (UK's DST)
- CET/CEST — Central European Time / Summer Time
- IST — Indian Standard Time (UTC+5:30) — but also Irish Standard Time!
- JST — Japan Standard Time (UTC+9)
- AEST/AEDT — Australian Eastern Standard/Daylight Time
Watch out for ambiguous abbreviations. "IST" can mean India, Ireland, or Israel. Always prefer the full name or the UTC offset.
Planning Meetings Across Time Zones
The work-hour strip in this tool shows, for each city, which hours are:
- Green (work hours) — 9 AM to 6 PM local time. Best for scheduling.
- Amber (off hours) — 6 AM to 9 AM and 6 PM to 10 PM. Acceptable with warning.
- Dark (sleep hours) — 10 PM to 6 AM. Try to avoid these.
The overlapping green regions show when everyone can meet without compromises. If there's no overlap, at least one person will need to take an early morning or late evening call.
Common Use Cases
- International business — schedule calls across continents
- Remote teams — find overlapping working hours
- Travel planning — know when to call home from abroad
- Online events — pick a time that works for global audiences
- Freelancing — coordinate with clients in other countries
- Family — plan calls with relatives living abroad
- Sports and broadcasts — know when a game starts in your time
Why Use This Tool Instead of Google?
- Multi-city view — see many cities side by side
- Work-hour strip — visual meeting planner
- No tracking — no Google search history
- Works offline — the browser does all the math locally
- Custom cities — pin the ones you care about
- 24-hour format — toggle for international use
Interesting Time Zone Facts
- China uses one time zone despite spanning five geographical zones.
- Russia has 11 time zones — the most of any country.
- Nepal is UTC+5:45 — one of the few quarter-hour offsets.
- Kiribati spans the International Date Line, so the country has days that overlap with itself.
- UTC replaced GMT as the global standard in 1972.
- Some countries have changed time zones mid-year — Samoa skipped an entire day in 2011.
Frequently Asked Questions
- How many cities are supported? — Around 400 cities covering every continent and major region.
- Does it handle DST? — Yes. DST is automatically applied based on the selected date.
- Are the times accurate? — Yes. Everything is computed using the browser's IANA time zone database.
- What if my city isn't listed? — Try a nearby major city with the same time zone. Or choose from the many entries.
- Can I add more cities? — Yes, use the dropdown to add any city to your world clock list.
- Is my data private? — Yes. No network requests, no tracking, no analytics.
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Privacy Note
Everything runs in your browser using the built-in JavaScript Date and Intl APIs. No data is sent to any server. No tracking, no cookies, no analytics.