Calculate factorials and combinations

Instantly compute n! (factorial), nCr (combinations), and nPr (permutations) for any valid integers.

Factorial Calculator

Compute n!, combinations (nCr), and permutations (nPr).

n (0–20)

r (for nCr / nPr)

Factorial Calculator is useful for statistics, probability problems, and combinatorics exercises in math courses and competitive programming.

Factorial (n!) calculation

Combinations (nCr) calculation

Permutations (nPr) calculation

Supports n up to 20

Instant client-side results

Covers factorial, nCr, and nPr in a single tool.

No calculator app needed for combinatorics problems.

Handles n up to 20 (maximum safe factorial in JavaScript).

What is n! (factorial)?

n! is the product of all positive integers from 1 to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120.

What is the difference between nCr and nPr?

nCr counts combinations where order does NOT matter. nPr counts permutations where order DOES matter.

Why is there a limit on n?

JavaScript numbers lose precision past 2^53. Factorials above 20! exceed that range.

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