Formula and calculator for the sum of a geometric progression

How to find the sum (S) of the first n numbers of a geometric progression on a calculator?

If you need to calculate the sum of the terms of a geometric progression, use our service. To calculate the sum, you need to enter the initial data: the value of any member of the geometric progression and its ordinal number; the denominator of the progression; its length. In the calculation results you will find out the solution to this problem – the sum of the numbers of the geometric progression. Please note that the calculator finds the sum of the progression terms, the number of which does not exceed 100.

Formulas for finding the sum of the first n terms of a geometric progression:

S_n = b₁ × (qⁿ – 1) ÷ (q – 1), b₁ – the first term of a geometric progression, n is the number of terms of the progression, q is the denominator of the progression.

S_n = b_n × (q – b₁) ÷ (q – 1), b_n – n-th term of the progression.

Depending on the known initial data, you can use the first or second formula. In addition, you can automate and simplify the process of calculating the sum of a geometric progression by using our calculator.