Ash Wednesday Date Calculator

In the Western Christian Church, Ash Wednesday marks the first day of Lent. It occurs exactly 46 days before Easter Sunday, which is the first Sunday after the Paschal Full Moon (PFM). Ash Wednesday may occur as early as February 4 or as late as March 10. The preceding day is Fat Tuesday or Mardi Gras.

Part of the Ash Wednesday ritual is having the sign of the cross marked on one's forehead with ashes. This is done as a sign of mourning and repentance to God, and to commemorate the beginning of Jesus's 40-day fast in the desert.

For any given year between 326 AD and 4099 AD, you can calculate the date of Ash Wednesday using Easter dating tables. You can also use the calculator on the left for dates between 1583 and 4099. See also the calculators for Good Friday and Palm Sunday.

Computing the Date of Ash Wednesday By Hand

To find the date of Ash Wednesday for a given year by hand, first calculate the date of Easter. To subtract 46 days from the answer, there are 5 possible cases depending on when Easter occurs and whether it's a leap year.

Case Ia: If Easter falls between March 22 and March 31 in a non-leap year, subtract 18 from the day number and change the month to February. For example, if Easter is on March 28, then Ash Wednesday is on February 10.

Case Ib: If Easter falls between March 22 and March 31 in a leap year, subtract 17 from the day number and change the month to February. For example, if Easter is on March 28, then Ash Wednesday is on February 11.

Case IIa: If Easter falls between April 1 and April 15 in a non-leap year, add 13 to the day number and change the month to February. For example, if Easter occurs on April 15, then Ash Wednesday occurs on February 28.

Case IIb: If Easter falls between April 1 and April 15 in a leap year, add 14 to the day number and change the month to February. For example, if Easter occurs on April 15, then Ash Wednesday occurs on February 29.

Case III: If Easter occurs between April 16 and April 25 in any year, subtract 15 from the day number and change the month to March. For example, if Easter falls on April 20, then Ash Wednesday falls on March 5.

Ash Wednesday on Leap Day

Ash Wednesday coincides with Leap Day, February 29, only in leap years where Easter falls on April 15. The first time this will ever occur is 2096. After that the next Ash Wednesday/Leap Day dates are in 2468, 2688, 2840, and 2992. Incidentally, these are years in which Good Friday is on the 13th.

© Had2Know 2010