No upload, 100% local, no account

Date details

Pick a date to see everything about it at a glance.

How Date details works

Date Details gives you a complete factual profile of any calendar date: the day of the week, the ISO week number, the quarter of the year (Q1 through Q4), the day-of-year count (1 through 365 or 366), whether the year is a leap year, and the Western zodiac sign for that date. All of this is derived from the single date you enter, with no lookup tables fetched from the internet.

Every field is computed by standard calendar arithmetic in your browser. The date you enter stays on your device: no form data is posted, no analytics event records what date you looked up. This approach also means the results are reproducible and deterministic; entering the same date on two different devices will always give the same output.

Written by Bastien Sulyan

How to use Date details, step by step

  1. Enter any date using the date picker or by typing in YYYY-MM-DD format.
  2. Review the day-of-week, ISO week number, quarter, and day-of-year values.
  3. Check the leap year indicator and the zodiac sign.
  4. Change the date to explore any other calendar date at any time.

Common use cases

  • A software engineer verifies the ISO week number for a date while debugging a weekly-report query that groups records by ISO week.
  • An astrology enthusiast confirms the Western zodiac sign boundary for a date near the end of a sign period.
  • A financial analyst checks which quarter a specific transaction date falls in, to assign it to the correct reporting period.
  • A curriculum planner looks up the day-of-year number for a school term start date to calculate elapsed teaching days.

Frequently asked questions

What standard does the week number follow?

ISO 8601. Under this standard, week 1 is the week containing the first Thursday of the year, and weeks run Monday to Sunday. This is the convention used by most European countries and many business systems. Note that ISO week 1 can start in late December of the previous year, and the last week of December can belong to ISO week 1 of the next year.

How is the zodiac sign determined?

The tool uses the fixed Western tropical zodiac boundary dates (for example, Aries runs from March 21 to April 19). No birth time or location is considered; only the calendar date. This is the same method used by newspaper horoscopes.

What counts as a leap year?

A year is a leap year if it is divisible by 4, except for century years, which must also be divisible by 400. So 2000 was a leap year, 1900 was not, and 2024 is. The calculation follows the Gregorian calendar rule.

Is the date I enter stored or transmitted?

Neither. The date is read by JavaScript running in this tab and all derived values are computed inline. Nothing is stored beyond your browser session, and nothing is sent to any server. Entering a date produces no network traffic.

Does day-of-year count from 0 or 1?

From 1. January 1 is day 1, December 31 is day 365 in a common year and day 366 in a leap year.

Can I look up dates before 1970 or far in the future?

Yes. The Gregorian calendar rules apply to any date the browser's Date object can represent, which covers a range of hundreds of thousands of years in either direction. Practical limits only appear at extreme dates.

Related tools

Keep everything local, explore complementary tools.

All date and time tools