Factorial Calculator
Calculate n! with digit count and trailing zeros.
How it works
n! is the product of every whole number from 1 to n, and 0! is defined as 1. Example: 5! = 5 × 4 × 3 × 2 × 1 = 120. Factorials count the ways to arrange n different items, and they grow extremely fast: 20! already has 19 digits.
FAQ
Is this calculator free?
Yes. No signup is needed and nothing you enter is stored.
Is the result exact?
Results are rounded for display. For financial, medical, or legal decisions, confirm with a professional.
Do my numbers leave my device?
No. The calculation runs in your browser.