Timezone Converter: Convert Times Between Any Two Timezones
Instantly convert times between any two of 400+ timezones worldwide, with DST indicators, UTC offsets, and shareable result URLs.
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Coordinating across timezones is one of the most error-prone tasks in both software development and everyday professional life. A meeting scheduled for 3 PM EST is 8 PM UTC, but is it 8 AM or 9 AM the next day in Tokyo? Is London on GMT or BST right now? Answering these questions incorrectly causes missed calls, broken integrations, and hard-to-reproduce time-dependent bugs.
Our Timezone Converter supports more than 400 IANA timezone identifiers — the same database used by operating systems and programming languages worldwide. Enter a date and time, select a source timezone, and instantly see the equivalent time in one or more target timezones. Each result clearly shows the UTC offset and a DST indicator so you always know whether daylight saving time is in effect.
The tool is designed for developers, remote teams, and anyone who regularly deals with international scheduling. You can add multiple target timezones to compare, and the result URL encodes your selections so you can share a pre-configured comparison with your team.
What Is a Timezone Converter?
A timezone converter is a tool that translates a specific date and time from one timezone to its equivalent in another, accounting for both the UTC offset of each timezone and whether daylight saving time is currently in effect. Simply adjusting by a fixed number of hours is insufficient because UTC offsets change with DST transitions, and different countries observe DST on different dates.
The gold standard for timezone data is the IANA Time Zone Database (also called the Olson database), which is maintained collaboratively and updated whenever countries change their timezone rules. It uses descriptive identifiers like America/New_York, Europe/London, and Asia/Tokyo rather than ambiguous abbreviations like EST or IST, which can refer to multiple different timezones depending on context.
Timezone conversion is critical for API integrations that use timestamps, distributed systems with components in multiple regions, scheduling features in web applications, and any team collaboration that spans multiple countries.
How to Use This Tool
Convert a time between timezones in seconds:
- 1
Enter the Date and Time
Use the date and time inputs to specify the moment you want to convert. The current date and time in your browser's local timezone are pre-filled for convenience.
- 2
Select the Source Timezone
Choose the timezone that the entered time is in. Search by city name (e.g., 'London'), timezone name (e.g., 'Pacific'), or UTC offset. The tool pre-selects your browser's detected timezone.
- 3
Add Target Timezones
Click 'Add Timezone' and search for any target timezone. Add as many as you need — all are displayed simultaneously in a clean comparison table.
- 4
Read the DST Indicators
Each result row shows the converted time, the full timezone name, the current UTC offset, and a DST badge if daylight saving time is active for that timezone on the selected date.
- 5
Share Your Comparison
Copy the page URL to share your exact timezone comparison with others — all selected timezones and the input time are encoded in the URL parameters.
Common Use Cases
Timezone conversion is needed in many professional and technical scenarios:
- Scheduling meetings and calls across international teams and confirming that all participants see the correct local time before sending calendar invites
- Debugging timestamp discrepancies in distributed systems where services in different AWS or GCP regions log events in different local times
- Configuring cron jobs, scheduled tasks, and database maintenance windows to run at the correct local time in a specific region
- Converting API response timestamps from UTC to user-local time for display in web and mobile application interfaces
- Verifying that daylight saving time transitions will not shift a scheduled event to an unintended time as clocks change
Tips and Best Practices
Minimize timezone-related bugs and confusion with these guidelines:
- Always store and transmit dates in UTC — convert to local time only at the point of display, and store the user's timezone preference separately so you can convert correctly on any device
- Use IANA timezone identifiers (America/Chicago) rather than abbreviations (CST/CDT) in code and configuration — abbreviations are ambiguous and can refer to multiple different offsets
- Test your time-sensitive features against dates that include DST transitions to confirm that your code handles the extra or missing hour correctly
- When scheduling recurring events, specify the rule in local time with a named timezone rather than as a fixed UTC offset — fixed offsets break when DST changes the offset
- For user-facing time displays, always show the timezone abbreviation or offset alongside the time so users can immediately verify they are seeing the correct local time
Frequently Asked Questions
What is the difference between UTC and GMT?
UTC (Coordinated Universal Time) is the international time standard used in computing. GMT (Greenwich Mean Time) is a timezone that equals UTC+0 during standard time but is technically a geographic timezone, not a standard. In practice, UTC and GMT are interchangeable for most purposes, but UTC is the correct term in software systems.
Why do timezone abbreviations like EST and IST cause confusion?
Many abbreviations are shared by multiple timezones. EST can mean UTC-5 (US Eastern Standard Time) or UTC+10 (Australian Eastern Standard Time). IST can mean India Standard Time, Ireland Standard Time, or Israel Standard Time. Always use IANA identifiers like America/New_York or Asia/Kolkata to avoid ambiguity.
When does daylight saving time start and end in each country?
DST rules vary by country and are updated periodically by governments. In the US, DST runs from the second Sunday in March to the first Sunday in November. In the EU, it runs from the last Sunday in March to the last Sunday in October. Many countries, including India, Japan, and China, do not observe DST at all.
Why does the converter show a different UTC offset than I expected?
The UTC offset shown reflects whether DST is currently in effect on the selected date, not just the standard offset. For example, America/New_York is UTC-5 during standard time and UTC-4 during daylight saving time. The converter always shows the correct offset for the specific date you entered.
Can I convert a time to a timezone that is not a full-hour offset from UTC?
Yes. Several timezones have half-hour or 45-minute offsets from UTC, including India (UTC+5:30), Nepal (UTC+5:45), and Iran (UTC+3:30). The converter handles all IANA timezone offsets correctly regardless of whether they are whole-hour, half-hour, or fractional offsets.
How do I convert times in JavaScript?
Use the Intl.DateTimeFormat API with a timeZone option, or a library like Luxon (DateTime.fromISO(isoString).setZone('America/Chicago')) or day.js with the timezone plugin. Avoid manual offset arithmetic, which breaks with DST transitions.
Does the tool support historical timezone conversions?
Yes. The IANA timezone database includes historical timezone rule changes going back decades. Selecting a past date applies the timezone rules that were in effect at that time, including any changes made before or after a country's DST rules were updated.
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