Use this geometric sequence sum calculator for worksheet math, quick review, and self-checking when you want a direct answer without rewriting the formula by hand.
Informational calculator only. Verify important outputs independently before legal, tax, medical, engineering, safety-critical, contractual, employment, or compliance use.
Enter job values, review the estimate, then use the decision hints before ordering or quoting.
S_n = a_1(1 - r^n) / (1 - r)Use the closed-form geometric sum formula when the ratio is not 1.
If the ratio equals 1, the sum is just the first term times n.
Keep more decimal places when the result will be reused in another formula, drawing, or comparison rather than read once and rounded.
Yes. The formula is stable and this tool only covers straightforward calculation.