Timezone Converter - World Time Zone Calculator
Convert any date and time between 38+ world timezones instantly. Compare clocks across major cities and swap zones with one click.
What Is a Timezone Converter?
A timezone converter translates a specific date and time from one timezone to another using the browser's built-in Intl.DateTimeFormat API. It automatically accounts for daylight saving time (DST) transitions, so you always get accurate results regardless of the time of year. Whether you're scheduling international meetings, coordinating with remote teams, or checking business hours abroad, this tool shows the exact local time in any major city around the world.
How to Use the Timezone Converter
- Set Date & Time — Enter a date and time manually, or click the "Now" button to auto-fill the current moment
- Choose Source Timezone — Select the timezone your input time is in (e.g., New York, London)
- Choose Target Timezone — Select the timezone you want to convert to (e.g., Tokyo, Sydney)
- View Result — The converted time, full date, and UTC offset difference appear instantly
- Swap Zones — Click the swap button to reverse source and target timezones
- World Clock — Scroll down to see the same moment displayed across 38 major cities
Why Use This Timezone Converter?
- DST-Aware — Uses the browser's Intl API which automatically handles daylight saving time transitions
- 38+ Cities — Covers every major timezone from Honolulu to Auckland, including half-hour offsets like Mumbai
- World Clock View — See the same moment in all 38 cities at a glance, perfect for global team coordination
- Instant Results — No page reload or button click needed; results update as you change any input
- Swap Button — Quickly reverse the conversion direction with one click
- Privacy First — Everything runs in your browser. No data is sent to any server
FreeToolbox vs Other Timezone Converters
| Feature | FreeToolbox | timeanddate.com | worldtimebuddy.com |
|---|---|---|---|
| Browser-based | Yes | No (server) | No (server) |
| DST-aware | Yes (Intl API) | Yes | Yes |
| World clock view | Yes (38 cities) | Yes | Yes (4 at a time) |
| No signup required | Yes | Yes | Free tier limited |
| No ads | Yes | Has ads | Has ads |
| Swap button | Yes | No | No |
FAQ
Does this tool handle daylight saving time?
Yes. The converter uses your browser's Intl.DateTimeFormat API, which has built-in timezone and DST data from the IANA timezone database. When you convert a date that falls during DST, the offset is automatically adjusted.
How many timezones are supported?
The tool includes 38 major cities covering all standard UTC offsets from UTC-10 (Honolulu) to UTC+13 (Auckland), including half-hour offsets like Asia/Kolkata (UTC+5:30) and Asia/Kathmandu (UTC+5:45 via browser support).
Can I see multiple city times at once?
Yes. The World Clock section at the bottom shows the selected moment converted to all 38 cities simultaneously. This is useful for finding overlapping work hours across global teams.
Is my data sent to a server?
No. All timezone calculations happen locally in your browser using JavaScript. No date, time, or location data is transmitted anywhere.
Why does the offset change for the same city at different dates?
Many regions observe daylight saving time, which shifts their UTC offset by one hour during part of the year. For example, New York is UTC-5 in winter but UTC-4 during summer DST.