Arithmetic Sequence Calculator
nth term and sum of an arithmetic series.
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Results update instantly as you type — no submit needed.
Results
- Term 20
- 98
- Sum of first n terms
- 1010
- Common difference
- 5
- First terms
- 3, 8, 13, 18, 23, 28, 33, 38, 43, 48
Quick answer
In an arithmetic sequence each term adds a fixed common difference, so the nth term is a₁ + (n−1)d.
aₙ = a₁ + (n−1)d, Sₙ = n/2 (a₁ + aₙ)
How to use the Arithmetic Sequence Calculator
- 1Enter the first term of the sequence.
- 2Enter the common difference between terms.
- 3Enter which term number you want.
Frequently asked questions
What if the difference is negative?
The sequence decreases; the formulas still work exactly the same.
How is this different from geometric?
Arithmetic adds a constant, geometric multiplies by a constant.