🌍 Time Zone Converter
Compare current time across cities worldwide. Select cities and see local times side by side.
📋 When to Use the Time Zone Converter
Remote teams and distributed companies use the Time Zone Converter to find overlapping hours across San Francisco, London, and Tokyo for sprint planning and daily standups. Freelancers with international clients check the local time before sending messages at 3 AM in their recipient's timezone. Event organizers plan global webinars — set the broadcast time in your zone and see exactly when viewers in Sydney, Mumbai, and Berlin will tune in. Travelers verify arrival times in local hours before booking flights. Friends and family in different countries coordinate video calls without mental UTC-offset math. Developers testing timezone-sensitive features use the datetime picker to simulate specific dates (like DST transition days) across multiple zones.
⚙️ How the Time Zone Converter Works
The converter uses the browser's built-in Intl.DateTimeFormat API with the timeZone option — part of the ECMAScript Internationalization API, available in all modern browsers without any CDN, library, or network request. Each city name ("Istanbul", "New York", "Tokyo", etc.) is passed as an IANA timezone identifier to the API, which queries the browser's internal timezone database (Unicode CLDR) to determine the correct UTC offset and localized time for that zone — including current Daylight Saving Time rules. Reference time: defaults to new Date() (your system clock), or a specific date/time via the datetime-local picker — useful for checking a meeting next week or a flight arrival next month. DST: handled automatically because the browser's timezone database includes DST transition dates; no manual adjustment or up-to-date rule downloads needed. Results display in 24-hour format (hour12: false) with medium date style for compact readability. Selected cities appear as removable chips; unselected cities show as "+ City" buttons. All computation is local — no time data is sent to any server.
How to Use the Time Zone Converter
- Set your reference time — Choose a date and time in the datetime picker (defaults to now).
- Add cities — Click "+ Add City" and pick from the preset list (Istanbul, New York, London, Tokyo, etc.). Add as many as you need.
- Compare times — Each city shows its local time side by side. Times automatically account for DST (daylight saving time).
- Plan meetings — Use the comparison to find overlapping business hours across time zones for scheduling calls and meetings.
Frequently Asked Questions
Does it handle daylight saving time (DST)?
Yes — automatically. The browser's built-in timezone database (Unicode CLDR) includes current DST transition dates for every region. When you select a date in summer, cities observing DST show their summer offset (e.g., New York shows GMT-4 instead of GMT-5, London shows GMT+1 instead of GMT+0). No manual adjustment or rule updates are needed — the browser handles it.
How many cities can I add?
You can add as many cities as you like. For practical use, 3-5 cities keep the display clean and readable.
Can I add custom cities?
The tool includes major world cities. For cities not listed, pick the nearest city in the same timezone. The time will be the same.
Why does my city show the wrong time?
The time comes from your browser's Intl.DateTimeFormat API, which relies on your operating system's timezone database. Make sure your device's system clock and timezone are set correctly. In rare cases, if a region recently changed its DST rules, you may need to install OS updates so the timezone database reflects the latest changes. Restarting your browser after an OS update ensures the new rules take effect.
Can I set a specific date and time, not just now?
Yes. Use the Date & Time picker at the top of the tool. Enter any past or future date and time, and all selected cities instantly update to show what the local time was or will be at that exact moment. For example: "My flight lands at Istanbul at 7 PM next Friday — what time is it in New York and Tokyo then?" The datetime picker makes planning across time zones precise.
What time zones are supported?
The tool includes 14 major cities covering all inhabited continents: Istanbul (GMT+3), New York (GMT-5/-4 DST), London (GMT+0/+1 DST), Tokyo (GMT+9), Dubai (GMT+4), Singapore (GMT+8), Sydney (GMT+11/+10 DST — note DST runs Oct–Apr in the southern hemisphere), Los Angeles (GMT-8/-7 DST), Berlin (GMT+1/+2 DST), Moscow (GMT+3, no DST), Paris (GMT+1/+2 DST), Mumbai (GMT+5:30, no DST), São Paulo (GMT-3), and Shanghai (GMT+8, no DST). If your city isn't listed, choose the nearest city in the same timezone — the local time will be identical.