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World Time Lab
  • Explore time around EarthWorld Clock

    See the live globe, local clocks, and places around the world.

    • Live World ClockExplore day, night, time zones, and pinned places.
    • Time by CitySearch current local time in cities worldwide.
    • Time by CountrySee every civil time zone used by a country.
    • Distance Between CitiesMeasure great-circle distance on a real globe.
    • Day & Night WidgetAdd the live day and night map to another site.
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  • Convert and coordinateTime Zones

    Translate city times, UTC offsets, and abbreviations without guesswork.

    • Time Zone ConverterCompare cities, PST, WAT, UTC offsets, and more in one view.
    • Meeting Time FinderFind working-hour overlap across as many as six locations.
    • Time Zone Conversion ChartsBrowse quick reference tables for common zone pairs.
    • Abbreviations ExplainedWhat PST, EST, GMT, CET and the rest actually mean.
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  • Follow the skySun & Moon

    Track sunlight, moon phases, eclipses, and the changing seasons.

    • Sunrise & SunsetFind solar times and day length for any listed city.
    • Moon PhasesSee the live Moon, moonrise, moonset, and phase calendar.
    • Solar & Lunar EclipsesExplore upcoming eclipses and local visibility.
    • Equinoxes & SolsticesUnderstand the tilt, sunlight, and season changes.
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  • Plan dates your wayCalendars & Dates

    Build calendars, count days, and answer practical date questions.

    • 2026 CalendarBrowse the full year with week numbers and holidays.
    • Printable Calendar MakerCustomize columns, colors, logos, holidays, PDF, and ICS.
    • Date CalculatorsAdd dates, count days, find weekdays, and check weeks.
    • Days Between DatesCalculate an exact calendar difference.
    • Add or Subtract a DateMove forward or backward by a duration.
    • Days UntilCreate or browse live event countdowns.
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  • Measure every momentTimers

    Count down, measure laps, or test your reaction speed.

    • Online TimerCount down or up with speed, precision, and optional sound.
    • StopwatchMeasure elapsed time and visual lap splits.
    • Reaction Time TestMeasure keyboard or tap response in milliseconds.
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  • Experiment with a worldPlanet Lab

    Change a planet, inspect the physics, and explore what-if scenarios.

    • Planet SimulatorBuild a world and see computed physical changes.
    • All What-If ScenariosBrowse climate, orbit, impact, and ocean experiments.
    • Snowball EarthFollow ice-albedo feedback across Earth.
    • Runaway GreenhouseExplore an illustrated Venus-like end state.
    • Asteroid ImpactReplay a staged impact, shock ring, and crater.
    • Mega-TsunamiWatch teaching wavefronts cross an ocean.
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Explore World Time Lab

Tools & guides

    • Live World Clock
    • Time by City
    • Time by Country
    • Distance Between Cities
    • Day & Night Widget
    • Time Zone Converter
    • Meeting Time Finder
    • Time Zone Conversion Charts
    • Abbreviations Explained
    • Sunrise & Sunset
    • Moon Phases
    • Solar & Lunar Eclipses
    • Equinoxes & Solstices
    • 2026 Calendar
    • Printable Calendar Maker
    • Date Calculators
    • Days Between Dates
    • Add or Subtract a Date
    • Days Until
    • Online Timer
    • Stopwatch
    • Reaction Time Test
    • Planet Simulator
    • All What-If Scenarios
    • Snowball Earth
    • Runaway Greenhouse
    • Asteroid Impact
    • Mega-Tsunami
About & data
About World Time LabMethodology & Data SourcesReport an ErrorContact
In this sectionCalendars & Dates
Calendars
  • 2026 Calendar
  • Printable Calendar Maker
  • 2025 Calendar
  • 2027 Calendar
  • 2028 Calendar
  • 2029 Calendar
  • 2030 Calendar
Date calculators
  • All Date Calculators
  • Days Between Dates
  • Add or Subtract a Date
  • Week Numbers
  • Day of the Week
Countdowns
  • Browse Days-Until Countdowns
Home/Date calculators/Day of the week

Day of the week for any date

Enter a date to see its weekday: a birthday, a historical date, or a deadline years out.

Pick a date.

Read a date without counting calendar squares

Choose the day, month, and year in the date field. The result updates immediately; there is no form to send and no account to create. Use it to check which weekday a birthday falls on, label an old photograph, or choose a date for a recurring event. For example, January 1, 2026 falls on a Thursday, and February 29, 2024 falls on a Thursday too.

Why the same date changes weekday

A common year has 365 days, or 52 weeks plus one day, so dates usually move forward one weekday the following year. A leap day can add another day's shift. Adding seven days always returns to the same weekday. The tool applies Gregorian leap-year rules, including the century exception: 2000 had a February 29, while 1900 did not.

Calendar dates and historical records

This is a date lookup, not a conversion between time zones. An event near midnight can fall on different local dates in two cities; first find its local date with the time zone converter, then look up that date here.

Results extend Gregorian calendar rules into the past. A historical record may use the Julian calendar or another local calendar instead. The tool does not convert those records or account for the dates a country skipped when it changed calendars. Check which calendar the original source uses before interpreting an old date.

Add or subtract from a dateAll date calculators
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World Time Lab shows live day and night across the planet. Sun positions are computed with standard NOAA solar equations, and local times come from your browser's own IANA time zone database, so every calculation on this site runs on your device. Pages also load analytics from Google, which makes its own network requests. The privacy and cookie pages set out exactly what that involves.

© 2026 World Time Lab · this build shipped September 7, 2026. Times are shown to the minute and can differ by a minute or two from horizon observations. Time zone boundaries derived from the timezone-boundary-builder project (ODbL); map shapes from Natural Earth; named administrative boundaries from geoBoundaries gbOpen with source years and licenses varying by country. City search data © GeoNames under CC BY 4.0, transformed for prefix search and updated July 2026. Seasons view climate groups derived from the Kottek et al. Koeppen-Geiger world map (2006). World Time Lab v2026.9.1.