Geometric Sequence Calculator
Calculate the nth term, common ratio and sum of a geometric sequence or series for free with this simple browser-based geometric sequence calculator.
Enter Values
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How to use this calculator
- Enter the first term, common ratio and term number.
- Press Calculate.
How it works
Each term multiplies by a fixed ratio. The nth term = first × ratio^(n − 1).
Worked example
2, 6, 18… (n=4). 4th term 54, sum 80.
Common mistakes
- Confusing the common ratio with the common difference — geometric sequences multiply, not add.
- Using a ratio of 1, which makes every term the same.
Frequently asked questions
What is a geometric sequence?
Each term is the previous one times a constant ratio. The nth term = a × r^(n − 1), where a is the first term and r the ratio.
How do I find the common ratio?
Divide any term by the one before it; in 2, 6, 18, 54 the ratio is 3.
What is the common ratio?
The fixed number each term is multiplied by. In 2, 6, 18… the common ratio is 3.
Related tools
- Arithmetic Sequence Calculator
- Arithmetic Series Sum Calculator
- Geometric Series Sum Calculator
- Fibonacci Calculator
- Average (Mean) Calculator
- GCD & LCM Calculator
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Cite this tool
Zerdly. (2026). Geometric Sequence Calculator. Retrieved from https://www.zerdly.com/tools/geometric-sequence-calculator/
Tip: Enter any known values to calculate the remaining results.
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