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Day of the Week Finder

Find which day of the week any past or future date falls on.

Which weekday is a date?

How it works

  1. The weekday is computed on the proleptic Gregorian calendar (the international standard) directly from the parsed date, never from a millisecond difference.
  2. Centuries are handled correctly: 1900 and 2100 are not leap years (divisible by 100 but not 400), and the engine’s unit tests pin those cases down.
  3. The ISO week number and the day-of-year are shown alongside, since the three answers usually travel together in planning and reporting.

Good to know

  • Works across the full Gregorian range the engine supports, centuries back and forward.
  • Dates from eras that used the Julian calendar historically will not match historical local usage; the Gregorian assumption is stated rather than hidden.
  • Pair it with the Week Number tool for reporting weeks and the Business Days tool for working-day math.
Date Calculators

Week Number Calculator

Find the ISO 8601 week number and week year for any date.

Open Tool
Date Calculators

Date Difference Calculator

Break down the gap between two dates into years, months and days.

Open Tool
Date Calculators

Days Until a Date

Count down the days from today to any future or past date.

Open Tool
Date CalculatorsFeatured

Age Calculator

Calculate exact age in years, months, and days plus next birthday countdown.

Open Tool

Frequently asked questions

How far back and forward does it work?
Across the full Gregorian calendar range supported by the engine, centuries back and forward, including leap-year exceptions like 1900 and 2100.
Is the Gregorian calendar assumed?
Yes, the proleptic Gregorian calendar, which is the international standard. Dates from eras using the Julian calendar will not match historical local usage.
Why does the weekday matter for planning?
Weekday drives business days, delivery windows, event scheduling, and recurring routines. The finder pairs with the Business Days and Week Number tools.