Factorial Calculator
Exact factorials up to 10,000! with digit counts, trailing zeros and scientific notation.
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How to use
- Type a whole number from 0 to 10,000.
- See the size, digit count and trailing zeros instantly.
- Copy or download the exact value with every digit.
How it works
n! is the product of all whole numbers from 1 to n, and 0! is 1 by definition. The calculation uses arbitrary-precision integers, so every digit is exact. Trailing zeros are counted with Legendre’s formula (the number of factors of 5).
Limitations
- The limit is 10,000! (35,660 digits) to keep the page responsive on modest devices.
Privacy
Your text is processed entirely in this browser tab. Nothing is uploaded, logged or saved by this tool.
Local processing protects your data from being uploaded, but it cannot protect against a compromised device or malicious browser extensions.