ganak.appWeekday Finder
Find weekday and day-of-year for any date.
Pick a date to find the weekday
What Day of the Week Is Any Date?
Instantly find the weekday, day-of-year, and remaining days for any date
The weekday calculator (also called a day of the week calculator) instantly tells you what day any date falls on. Whether you want to know "What day of the week was I born?", "What day is Christmas this year?", or "What day was July 20, 1969?" — just select the date and get your answer.
Beyond the weekday, the calculator shows the day-of-year number (also called ordinal date or DOY) and how many days remain in the year. The day-of-year is used in aviation, agriculture, astronomy, military date formats, and data science for seasonal analysis.
What You Get for Any Date
Weekday
Mon – Sun
Day #
1 – 366
Days Left
In the year
Famous Dates & Their Weekdays
Historical and notable dates with their day-of-the-week
| Date | Weekday | Day of Year | Event |
|---|---|---|---|
| 15 Aug 1947 | Friday | 227 | India Independence Day |
| 20 Jul 1969 | Sunday | 201 | Moon Landing |
| 1 Jan 2000 | Saturday | 1 | Y2K / Millennium |
| 11 Sep 2001 | Tuesday | 254 | 9/11 Attacks |
| 29 Feb 2024 | Thursday | 60 | Leap Day 2024 |
| 1 Jan 2025 | Wednesday | 1 | New Year 2025 |
| 25 Dec 2025 | Thursday | 359 | Christmas 2025 |
| 1 Jan 2030 | Tuesday | 1 | New Year 2030 |
Interesting Facts About Each Day of the Week
Origins and cultural significance of weekday names
Named after the Moon (Moon's day). Most meetings are scheduled on Mondays. It's statistically the most common day for heart attacks.
Named after the Norse god Tyr. In many Spanish-speaking cultures, Tuesday the 13th (not Friday) is considered unlucky.
Named after Odin (Woden's day). Often called 'hump day' as it marks the midpoint of the workweek.
Named after Thor (Thunder's day). Thanksgiving in the US always falls on the 4th Thursday of November.
Named after the goddess Frigg. The most popular day for restaurant dining, movie releases, and product launches.
Named after the Roman god Saturn. The first day of the weekend in most Western cultures. Derived from Latin 'Saturni dies.'
Named after the Sun (Sun's day). Considered the first day of the week in some calendar systems (US) and the last in others (ISO).
When Do You Need a Weekday Calculator?
Common reasons to look up the day of the week
Birthday & Event Planning
Check which day of the week a birthday, anniversary, wedding, or holiday falls on for any year. Plan events on preferred days.
Historical Research
Find out what day of the week historical events occurred. Journalists, historians, and quiz enthusiasts frequently look up weekdays for past dates.
Scheduling & Meetings
Verify whether a date falls on a weekday or weekend before booking meetings, appointments, or flights.
Year-End Planning
Use the 'days remaining in year' feature to track progress toward annual goals, plan Q4 activities, and set year-end deadlines.
Day-of-Year (DOY) Lookups
Aviation uses DOY in flight plans. Agriculture tracks planting/harvesting by DOY. Scientists use it for seasonal data analysis.
Trivia & Personal Curiosity
What day were you born on? What day did significant personal events happen? Satisfy curiosity about meaningful dates in your life.
How the Day-of-Week Cycle Works
Understanding the 7-day cycle and calendar mathematics
The 7-day week cycle has been unbroken for thousands of years. Since a common year has 365 days (52 weeks + 1 day), each year starts one day later than the previous year. A leap year adds an extra shift, making the next year start two days later.
Calendar Cycle
The Gregorian calendar repeats exactly every 400 years (146,097 days = 20,871 weeks exactly). Within this cycle, there are 97 leap years and 303 common years.
Identical Calendars
Two years have identical calendars (same weekdays for all dates) when they start on the same day and are both common or both leap years. This happens every 6, 11, or 28 years depending on the leap year pattern.
Weekday Calculation Methodology
The mathematics behind finding the day of the week
This calculator uses the standard Gregorian calendar algorithm to determine the day of the week. The mathematical approach (related to Zeller's congruence) considers:
- Year contribution: Each year shifts the weekday by 1 (common year) or 2 (leap year)
- Century adjustment: The Gregorian calendar skips century leap years (except 400-divisible ones)
- Month offsets: Each month has a fixed offset based on its length (e.g., March starts 3 days after February in a non-leap year)
- Day-of-year: Computed by summing the days in all preceding months plus the day of the month
- Days remaining: 365 (or 366) minus the day-of-year number
The result is deterministic — every date maps to exactly one day of the week. This calculator gives the same results as Excel's WEEKDAY() function and Python's datetime.weekday() method.
Frequently Asked Questions
Common questions about finding the day of the week for any date
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Last updated Mar 17, 2026