Math
Geometric Sequence Calculator
Use this geometric sequence calculator for patterns that multiply by the same common ratio each step.
Try an example
Result
nth term
—
- Sum through n
- —
Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What the geometric sequence calculator solves
Use this geometric sequence calculator for patterns that multiply by the same common ratio each step.
Formula
How to use it
- Enter the first term.
- Enter the common ratio.
- Enter which term number you want.
How to read the answer
Geometric sequences grow by repeated multiplication, so they can increase or shrink much faster than arithmetic sequences.
Common mistakes and edge cases
- Use ratio, not difference.
- A ratio of 1 needs the special sum formula.
- Negative ratios alternate signs.
Worked examples
Doubling sequence
nth term
384
Decay sequence
nth term
3.125
Frequently asked questions
What is the common ratio?+
It is the multiplier from one term to the next.
Can the ratio be negative?+
Yes. The terms alternate signs when the ratio is negative.
About this calculator
- Written by
- mathcheck editorial team
- Last reviewed
- May 15, 2026
Method
- Uses the values entered by the user and stable formulas documented on the page.
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Last updated: May 15, 2026