Arithmetic Sequence Calculator: Find Nth Term & Sum

What makes a sequence arithmetic

An arithmetic sequence changes by a constant difference $d$ from one term to the next.

That gives the nth-term rule $a_n = a_1 + (n-1)d$ and the sum rule $S_n = rac{n}{2}(2a_1 + (n-1)d)$ .

The preview cards make that repeated step visible instead of leaving the pattern hidden inside a formula.

Homework involving arithmetic progressions.
Checking repeated equal increments in savings, scoring, or staircase-style patterns.
Verifying partial sums before writing a closed-form solution.

Generate geometric sequence terms, inspect any nth term, and read the ratio pattern from a compact visual calculator.

Easily calculate the sum of arithmetic and geometric series with our interactive online tool.

Generate the Fibonacci sequence up to a specified number of terms.