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Geometric Sequence nth Term Calculator

a_n = a₁ · r^(n−1).

Calculates the nth term and partial sum of a geometric sequence from the first term, common ratio, and term index n.

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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

a_n = a₁ · r^(n−1); S_n = a₁·(1 − r^n)/(1 − r)

In depth

Calculates the nth term and partial sum of a geometric sequence from the first term, common ratio, and term index n.