Math

Factorial Calculator

Calculate the factorial n! of a whole number.

By TheCalcTools Updated Formula checked and tested

Your numbers

Your results

n!
n!
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log₁₀(n!)
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Factorial Calculator by TheCalcTools

How the Factorial Calculator works

Enter a whole number from 0 to 170.

The calculator multiplies every whole number from 1 up to n.

Beyond 170 the result is too large for standard double-precision numbers.

The formula

n! = n × (n − 1) × … × 2 × 10! = 1

Worked example

Using the default values shown in the calculator:

n10
  1. 10! = 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1.
  2. 10! = 3,628,800.

Result:

n!3,628,800
log₁₀(n!)6.5598

Frequently asked questions

Why is 0! equal to 1?

There is exactly one way to arrange zero items: do nothing. It also keeps formulas such as combinations consistent.

Where are factorials used?

In counting arrangements (permutations), combinations, probability and series expansions.

Sources and further reading

Permutation and Combination CalculatorCount how many ways you can choose r items from n, with order (permutations) or without… Fibonacci Number CalculatorFind the nth Fibonacci number, where each number is the sum of the two before it GCD and LCM CalculatorEnter two whole numbers to find their greatest common divisor and least common multiple Prime Factorization CalculatorEnter a whole number to break it into prime factors Prime Number Calculator (Is It Prime? Next and Previous Prime)Enter a whole number to test whether it is prime Factors Calculator (All Divisors of a Number)Enter a whole number to list all of its factors

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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.