Enter the number of Aces, Kings, Queens, Jacks, and other cards in the longest suit into the calculator to determine the estimated number of tricks to win.

Rule Of 13 Formula

The following formula is used to calculate the estimated number of tricks a player might win in a bridge game using the Rule of 13.

ET = 13 - (A + K + Q + J + LS)

Variables:

  • ET is the estimated number of tricks to win
  • A is the number of Aces in hand
  • K is the number of Kings in hand
  • Q is the number of Queens in hand
  • J is the number of Jacks in hand
  • LS is the number of other cards in the longest suit

To calculate the estimated number of tricks to win, count the number of Aces, Kings, Queens, and Jacks in your hand, and add the number of other cards in your longest suit. Subtract this total from 13. The result is an estimate of the number of tricks you might win.

What is a Rule Of 13?

The Rule of 13 is a method used in bridge card game to estimate the number of tricks a player might expect to win based on the cards in their hand. The player counts the number of Aces, Kings, Queens, and Jacks they have, then adds the number of other cards in their longest suit. The total, subtracted from 13, gives an estimate of the number of tricks the player might lose, and hence indirectly, the number of tricks they might win.

How to Calculate Rule Of 13?

The following steps outline how to calculate the Rule Of 13.


  1. First, determine the number of Aces in hand (A).
  2. Next, determine the number of Kings in hand (K).
  3. Next, determine the number of Queens in hand (Q).
  4. Next, determine the number of Jacks in hand (J).
  5. Next, determine the number of other cards in the longest suit (LS).
  6. Finally, calculate the Rule Of 13 using the formula: ET = 13 – (A + K + Q + J + LS).

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Number of Aces in hand (A) = 2

Number of Kings in hand (K) = 1

Number of Queens in hand (Q) = 3

Number of Jacks in hand (J) = 0

Number of other cards in the longest suit (LS) = 4