Factorial Calculator – Solve n!

Enter a number to calculate the factorial n! using the calculator below.

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Factorial Number:

n! =

 

Learn how we calculated this below

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On this page:

• Calculator
• How to Calculate a Factorial
• Factorial Formulas
• Product Notation
• Recurrence Relation
• Factorial Table

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By

Joe Sexton

Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.

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Cite As:

Sexton, J. (n.d.). Factorial Calculator – Solve n! Inch Calculator. Retrieved November 17, 2024, from https://www.inchcalculator.com/factorial-calculator/

How to Calculate a Factorial

In mathematics, the factorial of a number n! is equal to the product of all positive integers up to and including the number. This holds true for all positive whole numbers.

One notable case to be aware of is that the factorial of 0! is equal to 1.

Factorial Formulas

The formula to calculate a factorial for a number is:

n! = n × (n-1) × (n-2) × … × 1

Thus, the factorial n! is equal to n times n minus 1, times n minus 2, continuing until the number 1 is reached.

We can also express the factorial formula a little differently.

n! = 1 × 2 × 3 × … × n

Written a little differently, this states that the factorial n! is equal to 1 times 2 times 3 times each number, repeating until it reaches the number n.

Product Notation

The factorial formula can also be expressed using product notation like this:

Recurrence Relation

And the formula expressed using the recurrence relation looks like this:

n! = n × (n – 1)!

So the factorial n! is equal to the number n times the factorial of n minus one. This recurses until n is equal to 0.

Factorial Table

The table below shows the factorial n! for the numbers one to one-hundred.