Home   Calendar   Holidays   Square Root Day

May5 Fun Holiday – Square Root Day

Square Root Day is celebrated on a day where the first two digits in the date are the square root of the last two digits. Only date formats that have the month and date first and the last two digits of the year last (mm/dd/yy, m/d/yy, dd/mm/yy or d/m/yy) can have Square Root Days.

Celebrate mathematics on Square Root Day.

©bigstockphoto.com/Wavebreak Media Ltd

Ron Gordon, a high school teacher in the State of California, United States is credited as the creator of this unofficial holiday. The first Square Root Day ever was celebrated on September 9, 1981 (09/09/81).

Opposite to Squaring

An important mathematical concept, the square root of a number (x) is another number (y) that, when multiplied by itself returns the first number (x). In other words, the square root of x is y, because y X y or y² is x.

To make it clearer, let's take an actual number example: the square root of 25 is 5, because when we multiply 5 by itself (5 X 5) or square it (5²), we get 25.

Rare Dates

Only 9 dates every century qualify to be a Square Root Day. The first day of the 21st century, January 1, 2001 (01/01/01) was a Square Root Day. Other past and future Square Root Days in this century are:

  • February 2, 2004 (02/02/04): 2 X 2 or 2² = 4
  • March 3, 2009 (03/03/09): 3 X 3 or 3² = 9
  • April 4, 2016 (04/04/16): 4 X 4 or 4² = 16
  • May 5, 2025 (05/05/25): 5 X 5 or 5² = 25
  • June 6, 2036 (06/06/36): 6 X 6 or 6² = 36
  • July 7, 2049 (07/07/49): 7 X 7 or 7² = 49
  • August 8, 2064 (08/08/64): 8 X 8 or 8² = 64
  • September 9, 2081 (09/09/81): 9 X 9 or 9² = 81

Other Mathematical Holidays

You don't have to wait for Square Root Day to celebrate a unique mathematical holiday. There are several other mathematical holidays throughout the year that honor mathematicians and their work. Some of these include Pythagorean Theorem Day, e-Day, Pi Day, Tau Day, Yellow Pig Day, Pi Approximation Day, and Fibonacci Day.

How to Celebrate?

  • Learn more about the real-life and mathematical applications of square root.
  • Eat square shaped food, made specifically from root vegetables the whole day. May we recommend square sweet potato fries, square potato gratin, and a square carrot cake.
  • Spend the day learning about other special date patterns. Use our Date Pattern Calculator to find out when's the next Sequential or Palindrome Day.

Did You Know...

...that the symbol for square root (√) is called the radix or the radical sign and was first used in print in 1525?

Square Root Day Observances

Fun Holiday: Square Root Day Observances
2025MonMay 5Square Root Day

See all Fun Holidays

Other Fun Holidays around May 5

6 May

Free Comic Book Day

Participating comic book stores give out free comic on Free Comic Book Day which is celebrated annually on the first Saturday of May.

4 May

Star Wars Day

Fans of Star Wars have created Star Wars Day to celebrate the hugely popular sci-fi film series set in a galaxy far, far away.

6 May

Beverage Day

Beverage Day recognizes the role that beverages play in the social and economic world.