Day of the Week Finder

How to use

1. Pick a Date — Choose any date — past, present, or future. The Gregorian calendar is used.
2. Read the Day — Instantly see the weekday, ISO week number, day of year, and leap-year status.
3. Check Distance — See exactly how many days the chosen date is from today.

Free Day of the Week Finder

Instantly find what day of the week any date falls on — past, present, or future. Also see the ISO week number, day of the year, leap-year status, and how many days the date is from today.

Common Uses

• Find what day a future birthday or anniversary lands on
• Verify historical dates for research or genealogy
• Look up the ISO week for project planning
• Determine if a year is a leap year
• Count days between today and a target date

How the Calculation Works

The tool uses JavaScript's built-in Gregorian calendar arithmetic, which handles leap years (including the every-100-and-400-year rules) and produces correct weekdays for any date between roughly 271,821 BC and 275,760 AD.

Privacy

All calculation happens locally. No date is transmitted.

Related: Date Difference Calculator, Age Calculator, Unix Timestamp Converter.

Frequently asked questions

What calendar does this use?

The proleptic Gregorian calendar (introduced in 1582). Dates before that are extrapolated and may differ from historical Julian-calendar records.

Why is the ISO week useful?

ISO 8601 week numbers (1–53) are the international standard for business calendars, project planning, and supply-chain scheduling. Week 1 always contains the first Thursday of the year.

Does it account for time zones?

The tool uses your local time zone at noon to avoid ambiguity around midnight. The weekday for any given calendar date is the same worldwide.

What's a leap year?

A year divisible by 4, except century years which must also be divisible by 400. So 2000 was a leap year but 1900 was not. Leap years have 366 days with a Feb 29.

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