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Arithmetic Sequence Calculator

n-th term and sum of an arithmetic sequence.

Compute the n-th term and the sum of the first n terms of an arithmetic sequence from its first term and common difference.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

aₙ = a₁ + (n − 1) · d; Sₙ = n · (a₁ + aₙ) / 2.

In depth

Compute the n-th term and the sum of the first n terms of an arithmetic sequence from its first term and common difference.