Enter Date
October 21, 2026 is a
Wednesday
October 2026
| Sun | Mon | Tue | Wed | Thu | Fri | Sat |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | ||||
| 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 |
| 18 | 19 | 20 | 21 | 22 | 23 | 24 |
| 25 | 26 | 27 | 28 | 29 | 30 | 31 |
Detailed Information
Day of Week
Wednesday
Day Number
3 (0=Sun)
Day of Year
294
Week Number
43
Quarter
Q4
Days in Month
31
Leap Year?
No
Julian Day
2,461,335
Zodiac Sign
Libra
Try Historical Dates
Date Information
Day of Week
Wednesday
October 21, 2026
Quick Answer
To find the day of week for any date: use our calculator or the Doomsday algorithm. Every year has "Doomsday" dates that fall on the same weekday: 4/4, 6/6, 8/8, 10/10, 12/12, and the last day of February. From these anchor dates, count forward or back. Example: December 9, 2026 is a Tuesday. Birthdays cycle through all days over ~5-6 years.
Key Facts
- Days of week cycle every 7 days perpetually
- Gregorian calendar repeats exactly every 400 years
- Same date falls on same weekday every 5, 6, or 11 years (varies)
- January 1, 2000 was a Saturday
- Leap years shift subsequent dates by 2 days; normal years by 1
- Doomsday algorithm uses anchor dates (4/4, 6/6, 8/8, etc.)
- Most centuries have different Doomsday anchors
- Friday the 13th occurs 1-3 times per year
Frequently Asked Questions
How do I find the day of the week for any date?
Use the Zeller's congruence or Doomsday algorithm. This calculator uses JavaScript's Date object which handles all calendar complexities including leap years, month lengths, and Gregorian calendar rules.
What is a leap year?
A leap year has 366 days (February 29th exists). Years divisible by 4 are leap years, EXCEPT years divisible by 100, UNLESS also divisible by 400. So 2000 was a leap year, but 1900 was not.
What is a Julian day?
Julian Day Number (JDN) counts days since January 1, 4713 BC (Julian calendar). Used by astronomers and historians to calculate time spans between dates across different calendar systems. Not related to the Julian calendar.
How are week numbers calculated?
ISO week numbering starts Monday. Week 1 is the first week with a Thursday (or containing Jan 4th). Some years have 52 weeks, others have 53. Different countries use different conventions.
What day was I born on?
Enter your birth date in the calculator to find out! Fun fact: The day you were born affects which day your birthday falls on each year. Birthdays advance by 1 day each year, or 2 days after a leap year's February.