Compute n! with exact integer arithmetic, live validation, and a readable summary for large outputs.
Last updated: June 2026 | By Patchworkr Team
n! means 1 x 2 x 3 x ... x n. By convention, 0! is defined as 1 so combinatorial formulas stay consistent.
The calculator can compute exact values through 170!, which still fits within finite JavaScript number limits for display and safely within BigInt for arithmetic.
Example: 5! = 5 x 4 x 3 x 2 x 1 = 120.
Calculate 4!
1. Start with 4.
2. Multiply 4 x 3 x 2 x 1.
3. Evaluate step by step to get 24.
Final answer: 24
It keeps combinatorial identities consistent and represents the single way to arrange zero objects.
170! is the last factorial that stays finite in JavaScript number display. Larger values quickly become unwieldy.
Not in this calculator. Factorials are defined here only for non-negative integers.
Yes. The factorial is computed with BigInt so the result is exact, not rounded.
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