❗ Factorial Calculator
Calculate the factorial of any non-negative integer. Handles large numbers with BigInt, shows digit count and scientific notation — all in your browser.
Enter a non-negative integer to compute its factorial.
About the Factorial Calculator
This calculator computes the factorial of any non-negative integer up to 1000. Because factorials grow extremely fast, the tool uses JavaScript's BigInt type so results stay exact even for very large numbers. For inputs above 20, a scientific-notation approximation is also shown alongside the full result.
What is a factorial?
The factorial of a non-negative integer n, written as n!, is the product of all positive integers less than or equal to n. By convention, 0! = 1. Examples: 5! = 5 × 4 × 3 × 2 × 1 = 120, and 10! = 3,628,800.
How to use
- Enter a non-negative integer from 0 to 1000 in the input box.
- Click Calculate. The result panel shows
n!in full, the digit count, and (for n > 20) the scientific-notation form. - Use Copy result to copy the full number to your clipboard.
Frequently asked questions
Why is there a maximum of 1000? 1000! has over 2500 digits. Higher inputs would consume excessive memory and time for very little practical value.
Why BigInt instead of regular numbers? JavaScript's Number type can only safely represent integers up to about 2⁵³. Factorials quickly exceed this limit — 21! is already too large — so BigInt is required for exact results.
Is the scientific-notation value exact? It is rounded to a few significant figures for readability. The full BigInt result above it is the exact value.
Is my input stored? No. All calculation happens locally in your browser.