Timezone Converter

About Timezone Converter

A time zone is a region of the Earth that uses a uniform standard time for legal, commercial, and social purposes. Time zones are defined by their offset from Coordinated Universal Time (UTC), ranging from UTC-12 to UTC+14. The International Date Line marks where the calendar day changes, creating some of the most extreme time differences on Earth.

Daylight Saving Time (DST) is the practice of advancing clocks during warmer months to extend evening daylight. Approximately 70 countries observe DST, but the start and end dates vary widely. This creates a moving target for developers — the same timezone can have different offsets depending on the date. Not all time zones observe DST, and some have permanently adopted DST.

IANA Time Zone Database (tz database) is the definitive source for timezone information. It contains over 500 historical and current timezone entries, accounting for every known timezone change — including shifts due to political decisions, war, and DST policy changes. This database is built into most operating systems and programming languages.

Working with timezones in software is notoriously difficult. Common pitfalls include: storing local times without UTC offsets, assuming timezone abbreviations (EST, PST) are unique or consistent year-round, performing arithmetic across DST boundaries, and forgetting that timezone names like 'America/New_York' are more reliable than abbreviations or numeric offsets.

This tool uses the Intl API built into modern browsers to provide accurate timezone conversions. It supports all IANA timezones and displays the current time in any timezone alongside its UTC offset. Use it to coordinate across teams, schedule international meetings, or debug timezone-related issues in your applications.