Sum of First N Cubes Calculator

About this calculator

This calculator uses Nicomachus's theorem, a classical identity in number theory: the sum of the first n cubes, 1³ + 2³ + … + n³, always equals the square of the nth triangular number, (n(n+1)/2)². That's a striking result — a sum of cubes collapsing into a perfect square — and it means the answer can be computed instantly without adding a single term.

It's a staple example in discrete mathematics and proof-by-induction courses, and the closed-form formula is useful whenever an exact sum of cubes is needed for large n without brute-force summation.