Time & Timezone Tools

All time tools use the browser's built-in Intl API with the IANA timezone database, which contains the complete history and future rules for daylight saving time transitions in every timezone. Conversions, countdowns, and clocks are always accurate, even across DST boundaries.

The IANA (Internet Assigned Numbers Authority) timezone database (also called tz or zoneinfo) is the world's authoritative reference for timezone rules, maintained by a community of volunteers. It defines timezones using identifiers like 'America/New_York' and 'Asia/Tokyo', and is used by all major operating systems, programming languages, and browsers.

A timezone is a geographic region that follows the same standard time, identified by its name (e.g., 'US Eastern Time'). A UTC offset is the numerical difference from UTC at a specific moment (e.g., UTC-5 in winter or UTC-4 in summer for Eastern Time). A timezone includes the rules for when offsets change; an offset alone is just a number at a single point in time.

Russia has 11 timezones, the most of any country. The United States has 6 (including territories), Canada has 6, Brazil has 4, Australia has 3, and China officially uses only 1 (UTC+8) despite spanning what would geographically be 5 timezones. The widest single-country timezone span is Russia's, from UTC+2 to UTC+12.

Yes. All time and timezone tools are completely free to use with no account, subscription, or installation required. Everything runs in your browser, and no data is sent to any server.