Free Time Zone Converter

About This Tool

Coordinating across time zones is one of the most common challenges in a connected world. A meeting at 9 AM in New York is 2 PM in London, 6:30 PM in Mumbai, and 11 PM in Tokyo. Getting those conversions wrong can mean missed calls, delayed projects, and frustrated colleagues. This free time zone converter removes the guesswork by letting you pick any two of 20 major time zones and instantly see the converted time, the offset difference, and full date context including daylight saving adjustments. The built-in meeting planner goes further, displaying the current time in eight major business hubs so you can find overlapping hours at a glance. It supports the 12-hour AM/PM format most people use day-to-day and handles half-hour offsets like India Standard Time automatically. All conversions rely on the IANA timezone database, the same source used by operating systems and servers worldwide, so results stay accurate through every daylight saving shift.

How Time Zone Conversion Works

Every time zone is defined by its offset from Coordinated Universal Time (UTC). New York, for example, is UTC-5 during Eastern Standard Time and UTC-4 during Eastern Daylight Time. To convert from one zone to another, the tool calculates the UTC offset for both zones at the specific date and finds the difference.

Step-by-step conversion example:

• You select 9:00 AM Eastern Time (UTC-5) as your source.
• You select London (UTC+0) as the target.
• The difference is +5 hours, so the result is 2:00 PM.

The tool accounts for daylight saving time (DST) automatically. During summer, both the US and UK shift clocks forward, but they do so on different dates. This means the offset between New York and London can be +4, +5, or even +6 hours depending on the time of year.

Understanding the IANA Timezone Database

The IANA timezone database, sometimes called the tz database or Olson database, is the authoritative source for timezone rules. It is maintained by a community of volunteers and updated several times per year to reflect changes made by governments around the world.

Key facts about IANA identifiers:

• They follow the format Region/City, such as America/New_York or Asia/Tokyo.
• The city chosen is typically the largest city in that timezone region.
• Historical changes, like when a country moved to a different offset, are recorded and preserved.
• Abbreviations like EST or PST are ambiguous and not unique. IANA identifiers remove that ambiguity.

This converter uses IANA identifiers under the hood to guarantee correctness, especially around DST transitions where abbreviation-based tools often produce wrong results.

Daylight Saving Time Explained

Daylight Saving Time (DST) is the practice of advancing clocks by one hour during warmer months to extend evening daylight. Not all regions observe DST, and the start and end dates vary by country.

Common DST patterns:

• United States and Canada: Second Sunday of March to first Sunday of November.
• European Union: Last Sunday of March to last Sunday of October.
• Australia: First Sunday of October to first Sunday of April (southern hemisphere, so summer is reversed).
• Japan, China, India, Singapore: Do not observe DST at all.

Because DST changes are not synchronized globally, the offset between two cities can shift during certain weeks of the year. This tool automatically accounts for those transitions by querying live timezone data for the current date.

Scheduling Meetings Across Time Zones

Finding a meeting time that works for participants in multiple continents requires more than simple math. Here are practical strategies that distributed teams use:

• Anchor on overlap hours. Identify the 2-3 hour window where all participants are within normal working hours (roughly 8 AM to 6 PM local). For US-Europe teams, this is usually 8-11 AM Eastern / 1-4 PM London.
• Rotate the inconvenience. If a single overlap window does not exist (for example, a team spanning New York, London, and Tokyo), rotate meeting times weekly so the burden of early or late calls is shared equally.
• Use the meeting planner grid. The grid at the bottom of this tool shows current time in eight cities simultaneously. Scan the grid to quickly see which cities are in business hours right now.
• Beware of half-hour zones. India (UTC+5:30), Nepal (UTC+5:45), and parts of Australia (UTC+9:30) use fractional offsets. A meeting at 10:00 AM in New York starts at 8:30 PM in Mumbai, not 8:00 PM.

Common Time Zone Abbreviations and Their Offsets

Time zone abbreviations are convenient shorthand but can be confusing because some abbreviations refer to multiple zones. Here is a reference for the most frequently used ones:

• UTC / GMT +0:00 - The global reference point.
• EST / EDT -5:00 / -4:00 - Eastern US (New York, Miami, Toronto).
• CST / CDT -6:00 / -5:00 - Central US (Chicago, Houston, Mexico City).
• MST / MDT -7:00 / -6:00 - Mountain US (Denver, Phoenix). Note: Arizona does not observe DST.
• PST / PDT -8:00 / -7:00 - Pacific US (Los Angeles, Seattle, Vancouver).
• CET / CEST +1:00 / +2:00 - Central Europe (Paris, Berlin, Rome).
• IST +5:30 - India Standard Time (Mumbai, Delhi). Not to be confused with Irish Standard Time (+1:00).
• JST +9:00 - Japan Standard Time (Tokyo, Osaka). No DST.
• AEST / AEDT +10:00 / +11:00 - Australian Eastern (Sydney, Melbourne).
• NZST / NZDT +12:00 / +13:00 - New Zealand (Auckland, Wellington).

Because IST alone can mean India, Ireland, or Israel, it is always safer to use IANA identifiers (Asia/Kolkata, Europe/Dublin, Asia/Jerusalem) for unambiguous communication.

Frequently Asked Questions