Factorial Calculator

Calculate the factorial of any non-negative integer.

Factorial

3,628,800

Digit Distribution

Factorial Growth

Factorial

nn!Digits
011
111
221
361
4242
51203
67203
75,0404
840,3205
9362,8806
103,628,8007

Understanding Factorial

The factorial calculator computes the factorial of any non-negative integer instantly, showing the result and the step-by-step multiplication chain. Factorial, written as n followed by an exclamation mark, is the product of all positive integers up to n. For example, five factorial equals five times four times three times two times one, which equals one hundred twenty. Factorials grow extremely rapidly, making manual calculation impractical for anything beyond single-digit numbers. Ten factorial is over three point six million, while twenty factorial exceeds two quintillion. This calculator handles large numbers with precision, giving you exact results for factorials that would be impossible to compute by hand. Factorials are fundamental to combinatorics, probability theory, and mathematical analysis. They appear in permutations, combinations, binomial coefficients, Taylor series, and countless other mathematical contexts. Understanding factorials is essential for anyone studying discrete mathematics, statistics, or computer science. The calculator also shows the relationship between factorials and related concepts like gamma function for non-integer inputs. Use this free factorial calculator for homework verification, mathematical exploration, probability calculations, or any application requiring precise factorial values. The instant results save time and eliminate calculation errors for these computationally intensive operations.

Practical Example

n! = n × (n−1) × (n−2) × ... × 2 × 1. Special cases: 0! = 1, 1! = 1. Example: 5! = 5 × 4 × 3 × 2 × 1 = 120.

Frequently Asked Questions

What is a factorial?

A factorial (n!) is the product of all positive integers up to n — for example, 5! = 5 × 4 × 3 × 2 × 1 = 120.

What is 0 factorial?

0! is defined as 1 by convention because the empty product equals 1, and it makes formulas in combinatorics work cleanly.

Why do factorials grow so fast?

Each factorial multiplies by another integer, so values like 20! already exceed 2.4 quintillion.

What if I get a different answer when calculating manually?

First check your order of operations (PEMDAS/BODMAS), then verify your units are consistent. Common errors include rounding too early, sign mistakes, and incorrect formula application. Use this calculator to verify each step of your work.

Are there shortcuts or mental math tricks?

Yes! Many mathematical operations have estimation shortcuts. For example, squaring numbers ending in 5, using the distributive property, or applying benchmark fractions. While shortcuts help with estimates, always use exact calculations for important work.

Disclaimer: This calculator provides estimates for informational purposes only. Actual results may vary. Consult a qualified professional for personalized advice.

Comments