World Clock
View current time in 400+ cities with accurate day/night indicator and sorting options.
Use Tool →Time
Track time across the globe with tools powered by the IANA Time Zone Database. Calculate time differences, convert between zones, and compute dates with precision—all running locally in your browser.
These tools serve anyone who works across time zones — remote teams scheduling meetings across continents, developers converting Unix timestamps when debugging server logs, travelers planning itineraries that span multiple regions, and anyone calculating their exact age or the number of days between two dates. The world clock displays live local time for major cities worldwide, powered by the browser's built-in Intl.DateTimeFormat API for reliable, locale-aware formatting.
All time zone conversions rely on the IANA Time Zone Database (also called tz or zoneinfo), the same authoritative source used by operating systems, programming languages, and smartphone apps worldwide. The date calculator correctly handles leap years following the Gregorian calendar rules — a year is a leap year if divisible by 4, except for century years, which must also be divisible by 400. ISO 8601 date formatting is used throughout for unambiguous, internationally recognized date representation.
Time Zone Converter
Find the time difference between any two cities. Convert times across 600+ cities using the IANA time zone database with DST handling, UTC offsets, and a meeting planner.
Use Tool →Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates.
Use Tool →Time Calculator
Add, subtract, multiply, and divide hours, minutes, and seconds easily.
Use Tool →Age Calculator
Calculate exact age from birthdate in years, months, and days.
Use Tool →Pet Age Calculator
Convert your pet's age to human years using veterinary science — dogs (by size), cats, rabbits, ferrets, guinea pigs and hamsters.
Use Tool →Frequently Asked Questions
What is the IANA Time Zone Database?
The IANA Time Zone Database (also called tz or zoneinfo) is the authoritative source for time zone rules worldwide, maintained by a community of volunteers under IANA (Internet Assigned Numbers Authority). It tracks current and historical UTC offsets, daylight saving time transitions, and zone name changes for every region. Our tools use this database through your browser's built-in Intl API.
What is Unix time?
Unix time (also called POSIX time or Epoch time) counts the number of seconds that have elapsed since January 1, 1970 00:00:00 UTC, known as the Unix Epoch. It is the standard way computers track time internally. For example, Unix timestamp 1000000000 corresponds to September 9, 2001 at 01:46:40 UTC.
How does daylight saving time affect time zones?
Daylight saving time (DST) shifts clocks forward (typically by one hour) during warmer months to extend evening daylight. Not all regions observe DST—most of Africa, Asia, and South America do not. Our time zone tools automatically account for DST transitions using the IANA Time Zone Database, so conversions are always accurate for any date.
How do I convert between time zones for a meeting?
Use our time zone converter: select the source city and time, then add destination cities. The tool automatically accounts for daylight saving time differences. For recurring meetings, note that DST transitions happen on different dates in different countries — the U.S. changes in March/November while the EU changes in March/October — so the time difference between zones can shift seasonally. Always verify the converted time close to the meeting date to avoid scheduling errors.
How does the age calculator work?
Enter your birth date and the calculator shows your exact age in years, months, and days, plus total days lived, upcoming birthday countdown, and the day of the week you were born. The calculation accounts for varying month lengths (28–31 days) and leap years. It uses the Gregorian calendar, the international civil calendar standard defined by ISO 8601. Results update in real time as you change the input date.