Enter the nth term and the (n-1)th term into the calculator to determine the common difference. This calculator can also evaluate any of the variables given the others are known.

Common Difference Formula

d = a_n - a_{(n-1)}


  • d is the common difference
  • a_n is the nth term in the sequence
  • a_(n-1) is the (n-1)th term in the sequence

To calculate the common difference, subtract the (n-1)th term from the nth term in the sequence. This will give you the constant difference between consecutive terms in the sequence.

What is a Common Difference?

A common difference is a term used in arithmetic sequences to describe the constant difference between consecutive terms in the sequence. It is calculated by subtracting the preceding term from the succeeding term. For example, in the sequence 2, 5, 8, 11, the common difference is 3, because each term increases by 3 from the previous one.

How to Calculate Common Difference?

The following steps outline how to calculate the Common Difference using the formula: d = an – a(n-1).

  1. First, determine the value of an.
  2. Next, determine the value of a(n-1).
  3. Next, subtract the value of a(n-1) from the value of an.
  4. Finally, calculate the common difference (d).
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem:

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

an = 8

a(n-1) = 4