Factorial Calculator
Fill in the value and the answer updates as you type.
How the Factorial Calculator 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.
Inputs and results
The Factorial Calculator takes 1 input and gives 3 results.
What you enter
- Whole number (0 to 170) — starts at 10.
What you get
- Factorial (n!)
- Number of digits
- Trailing zeros
Example: Factorial Calculator with the starting values
With whole number (0 to 170) 10, the calculator returns:
| Factorial (n!) | 3,628,800 |
|---|---|
| Number of digits | 7 |
| Trailing zeros | 2 |
Change any value above and the results update straight away.
Factorial Calculator FAQ
How do I use the Factorial Calculator?
Enter whole number (0 to 170) in the fields, then read factorial (n!), number of digits and trailing zeros in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Factorial Calculator calculate?
Calculate n! with digit count and trailing zeros. It returns factorial (n!), number of digits and trailing zeros from the 1 value you provide.
What values does the Factorial Calculator start with?
It opens with whole number (0 to 170) 10 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Factorial Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Factorial Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.