About the Common Difference Calculator
Find the common difference of an arithmetic sequence from a list of terms or from two terms and their positions.
Also known as: find common difference, arithmetic difference, d in arithmetic sequence.
How to use this calculator
- Enter term value aₘ, position m, term value aₙ, position n.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Open “Step-by-step” to see how the answer was worked out.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
d = (aₙ − aₘ) / (n − m)
Worked example
Using the values pre-filled in the calculator above:
- Term value aₘ = 7
- Position m = 2
- Term value aₙ = 31
- Position n = 8
the calculator returns:
- Common difference d: 4
- First term a₁: 3
Working
d = (31 − 7) ÷ (8 − 2) = 4