Timezone Converter

What is a Timezone Converter?

A Timezone Converter converts a specific time from one time zone to another. You select the source time zone, enter the time, then select the target time zone to see the equivalent time instantly. International travelers, remote workers, global businesses, event planners, and anyone communicating across time zones use timezone converters to schedule calls, book flights, plan virtual events, or simply understand what time it is for someone in another part of the world. Instead of manually calculating UTC offsets and remembering DST rules for each time zone, the converter handles all the complexity automatically and shows you the exact corresponding time in your target zone.

How to convert time zones manually (the formula)

To convert a time from one zone to another manually: determine the UTC offset for both the source and target time zones. The formula is: Target Time = Source Time − Source Offset + Target Offset. For example, to convert 3:00 PM Eastern Daylight Time (EDT, UTC−4) to Pacific Daylight Time (PDT, UTC−7): Convert the source time to UTC: 3:00 PM + 4 hours = 19:00 UTC. Then convert UTC to the target: 19:00 − 7 hours = 12:00 PM PDT. So 3:00 PM EDT = 12:00 PM PDT. If daylight saving time is in effect, use the DST offset instead of the standard offset. For example, Eastern Standard Time (EST) is UTC−5, but Eastern Daylight Time (EDT) is UTC−4. Using the wrong offset shifts the result by one hour.

Example calculation

Suppose you are in London (BST, UTC+1) and want to know what time it is in Tokyo (JST, UTC+9) when it is 10:00 AM in London on July 15, 2025. London is on British Summer Time (BST = UTC+1). Convert London time to UTC: 10:00 AM − 1 hour = 09:00 UTC. Then convert UTC to Tokyo: 09:00 + 9 hours = 18:00 JST. So 10:00 AM in London is 6:00 PM in Tokyo the same day. The timezone converter shows this instantly, along with the date (note that when London is at 10:00 PM, Tokyo is already the next day at 6:00 AM). The tool also accounts for whether each zone is currently in DST or standard time.

Common mistakes

• Confusing standard time with daylight time — EST (UTC−5) and EDT (UTC−4) are both used in Eastern Time but at different times of year. Using the wrong one shifts the result by one hour.
• Forgetting that DST dates vary by country — The US and Europe start and end DST on different dates. A date in early March may be EST in the US but already BST in the UK (clocks spring forward later in the US).
• Ignoring the International Date Line — When converting between time zones with large offsets, the date may change. 10:00 PM in New York is 12:00 PM (noon) the next day in Tokyo.
• Using time zone abbreviations alone — "CST" can mean Central Standard Time (US), China Standard Time, or Cuba Standard Time. Always verify which CST is intended.
• Mixing AM/PM with 24-hour format — 12:00 AM is midnight, 12:00 PM is noon. Converting without this distinction can shift the result by 12 hours.

Frequently asked questions