Timezone Converter
Free online timezone converter. Convert time between any timezone — UTC, EST, PST, GMT, IST, JST and more. Handles daylight saving time automatically. Perfect for scheduling international meetings.
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How to Use Timezone Converter
Enter the Time to Convert
Type a date and time, or use the current time. The tool accepts ISO 8601 format (2025-01-15T14:30:00) and common date/time formats.
Choose Source and Target Timezones
Select the source timezone (where the original time is from) and the target timezone (where you want to convert to). Choose from all IANA timezone identifiers — region/city format like America/New_York or Asia/Tokyo.
View the Converted Time
The converted time shows the equivalent local time in the target timezone, accounting for DST rules. The UTC offset for both timezones is displayed for verification.
Common Timezone Conversions
| When it's 9:00 AM in... | Time in... |
|---|---|
| New York (EST/EDT) | 2:00 PM in London, 11:00 PM in Tokyo |
| San Francisco (PST/PDT) | 5:00 PM in London, 2:00 AM next day in Tokyo |
| London (GMT/BST) | 4:00 AM in New York, 6:00 PM in Tokyo |
| Beijing (CST, UTC+8) | 8:00 PM previous day in New York, 1:00 AM in London |
| Sydney (AEST/AEDT) | 6:00 PM previous day in New York, 11:00 PM previous day in London |
Frequently Asked Questions
What is a timezone?
A timezone is a region of the Earth that observes a uniform standard time. Timezones are identified by IANA identifiers like "America/New_York" (Eastern Time), "Europe/London" (GMT/BST), or "Asia/Tokyo" (JST). There are roughly 40 timezones worldwide, ranging from UTC-12 to UTC+14. Timezones also include daylight saving time (DST) rules, which automatically adjust the offset at specific dates.
Why does my converted time show a different day?
When converting between timezones with large offsets, the date can shift. 9:00 PM Friday in New York (UTC-5) is 11:00 AM Saturday in Sydney (UTC+11). This is completely normal and is why calendar apps always store times in UTC internally — to avoid date confusion when scheduling meetings across timezones.
What is UTC?
UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks and time. It does not observe daylight saving time. All other timezones are expressed as offsets from UTC, like UTC+8 (China Standard Time) or UTC-5 (Eastern Standard Time). For servers and databases, storing all timestamps in UTC and converting to local timezone only for display is a best practice.
How does daylight saving time affect conversions?
DST rules are timezone-specific and change historically. Our converter uses your browser's built-in Intl.DateTimeFormat API, which includes the current IANA timezone database. This means it correctly handles DST transitions for all timezones. A time in March may have a different UTC offset than the same clock time in July due to DST.
Timezone Conversion Best Practices
Timezone bugs are one of the most common and frustrating categories of software defects. A meeting scheduled for 9:00 doesn't show up at 9:00 in someone's calendar. An event published at midnight UTC appears to happen the wrong day in some timezones. Following a few rules prevents these issues.
Rules to Follow
- Store in UTC: All timestamps in databases and APIs should be in UTC. Convert to local timezone only at the display layer.
- Include timezone info: When sending timestamps, include the offset or timezone identifier — "2025-01-15T14:30:00+05:30" is unambiguous; "2025-01-15T14:30:00" is not.
- Use IANA identifiers: "America/New_York" correctly handles DST. "EST" is ambiguous (Eastern Standard Time exists in the US and Australia).
- Test DST boundaries: Always test your timezone logic at DST transition dates — the second Sunday in March and first Sunday in November for US timezones.