Factorial Calculator
Calculate n! exactly with BigInt math, review the formula expansion for smaller values, and keep large results readable with a scientific summary.
Calculate a factorial
Enter a non-negative integer and calculate its factorial with exact whole-number math in your browser.
This calculator accepts whole numbers from 0 through 1,000.
Enter a whole number to calculate n!
This page calculates the factorial exactly, shows the expansion for smaller inputs, and keeps large results readable with a scientific notation summary.
Why factorials matter in math
Factorials appear in permutations, combinations, probability, and many algebra and calculus exercises, so it helps to have a quick exact calculator for n! instead of multiplying long descending sequences by hand.
At a glance
03
quick takeaways built into this calculator section.
- 01
0! is defined as 1, which is why the calculator handles zero as a valid input.
- 02
Small inputs show the multiplication expansion so the math stays easy to follow.
- 03
Large inputs stay exact with BigInt math, while the scientific summary keeps the UI readable.
Factorial Calculator
This factorial calculator finds n! for a non-negative whole number and keeps the result readable even when the number becomes extremely large. For small inputs it also shows the step-by-step expansion so students can see how the multiplication works.
That makes the page useful for classroom math, permutations, combinations, probability problems, and anyone who wants a fast answer when a handheld calculator does not clearly show the factorial result.
What a Factorial Means
The factorial of a whole number multiplies that number by every positive integer below it down to 1.
n! = n x (n - 1) x (n - 2) x ... x 2 x 1Examples:
- 5! = 5 x 4 x 3 x 2 x 1 = 120
- 3! = 3 x 2 x 1 = 6
- 0! = 1
Why 0! Equals 1
This is a standard definition in mathematics that keeps permutation and combination formulas consistent. Even though it feels unusual at first, 0! = 1 is the correct value.
Large Factorials and Scientific Notation
Factorials grow very quickly. That is why the calculator keeps the exact result available but also shows a scientific-notation style summary for larger values so the layout stays readable.
Who This Calculator Helps
This page is useful for students working on probability, combinations, permutations, and introductory discrete math. It is also handy when you want to check a factorial on a calculator but the small screen makes large results hard to interpret.
If you also need related percentage or statistics support, you may find the Percentage Calculator and Mean, Median, Mode Calculator useful.
How to Use the Factorial Calculator
- Enter a non-negative whole number.
- Click Calculate.
- Review the exact factorial result, the digit count, and the scientific summary.
- Copy the full result if you need it elsewhere.
Frequently Asked Questions
How do you do a factorial on a calculator?
Many scientific calculators have an n! key, but this page lets you enter the integer directly and see both the exact result and a readable summary.
What does the exclamation mark mean in math?
When it appears after a non-negative whole number, it means factorial, which is repeated multiplication down to 1.
What is the factorial of zero?
Zero factorial is 1.
Is this factorial calculator free?
Yes. It is free to use in the browser.
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