Geometric Sequence Calculator
Find a term and finite sum of a constant-ratio sequence.
Your inputs
Calculation results
Formula & assumptions
Term = arⁿ⁻¹; sum = a(1−rⁿ)/(1−r), or na when r=1.
Values use the specified units. Calculations use floating-point arithmetic. Check input measurements and formula assumptions before applying the result.
Compare your scenarios
Save up to five results to compare changes side by side. Scenarios stay in this tab until you clear or reload it.
Using Geometric Sequence Calculator
Find a term and finite sum of a constant-ratio sequence.
- Enter first term, common ratio, term number using the units printed under each field.
- Choose Calculate, or enable live updates. Review the result labels and formula assumptions.
- Save scenarios to compare up to five variations, then copy the report or download JSON or CSV.
Example
First term: 2 units Common ratio: 2 ratio Term number: 8 terms Selected term: 256 Sum through term: 510
Questions & answers
What does Geometric Sequence Calculator calculate?
Find a term and finite sum of a constant-ratio sequence.
Which units should I enter?
First term uses units. Common ratio uses ratio. Term number uses terms. Convert values to these units before calculating.
Which formula does it use?
Term = arⁿ⁻¹; sum = a(1−rⁿ)/(1−r), or na when r=1.
What does the included example show?
First term: 2 units; Common ratio: 2 ratio; Term number: 8 terms. Result: Selected term = 256; Sum through term = 510.
Can I compare different settings?
Yes. Save a scenario, change the inputs and save another result. Up to five scenarios are compared in this tab; they disappear when you reload or leave.
Can I export the calculation?
Copy the JSON report or download JSON and CSV with inputs, result labels and numeric values. Processing uses local JavaScript; no calculation request is sent to our server. Displayed values use up to 10 significant digits; exports retain JavaScript numeric precision.
Related tools
A useful next step for your task.
Everyday CalculatorsPermutation CalculatorCount ordered selections without replacement.
Everyday CalculatorsCombination CalculatorCount unordered selections without replacement.
ConvertersUnit ConverterRecommendedConvert length, mass, temperature, area, volume, speed, time and digital storage. Strict inputs, batch reports and clearly labeled US, imperial…
Everyday Calculators2D Point Distance CalculatorMeasure the straight-line distance and midpoint between coordinates.
Help improve this tool
Report a problem or suggest an improvement
Describe the issue without pasting private tool input. Feedback goes to our admin inbox.