Enter the total number of letters and the number of letters to be chosen at a time into the calculator to determine the number of combinations.

Letter Combination Formula

The following formula is used to calculate the number of possible combinations of letters.

C = n! / (r!(n-r)!)

Variables:

  • C is the number of combinations
  • n is the total number of letters
  • r is the number of letters to be chosen at a time
  • ! denotes factorial, which is the product of all positive integers up to that number

To calculate the number of possible combinations of letters, first calculate the factorial of the total number of letters. Then, calculate the factorial of the number of letters to be chosen at a time, and the factorial of the difference between the total number of letters and the number of letters to be chosen at a time. Finally, divide the first result by the product of the second and third results.

What is a Letter Combination?

A letter combination refers to the arrangement of letters in a specific order. It can be a part of a word, a whole word, or a series of words. These combinations can be used in various fields such as cryptography, linguistics, and computer science. In the English language, certain combinations are more common than others, and understanding these can help in areas such as spelling, pronunciation, and language learning.

How to Calculate Letter Combination?

The following steps outline how to calculate the Letter Combination using the formula: C = n! / (r!(n-r)!)


  1. First, determine the total number of letters (n).
  2. Next, determine the number of letters to be chosen at a time (r).
  3. Next, calculate the factorial of n, denoted as n!.
  4. Next, calculate the factorial of r, denoted as r!.
  5. Next, calculate the factorial of (n-r), denoted as (n-r)!
  6. Finally, calculate the Letter Combination using the formula C = n! / (r!(n-r)!).
  7. After inserting the values of n and r and calculating the result, check your answer with a calculator.

Example Problem:

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

Total number of letters (n) = 5

Number of letters to be chosen at a time (r) = 3