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Factorial Calculator

Compute factorials and double factorials exactly, with digit counts to match.

Compute a factorial

Result: —
Digits: —
Scientific: —
Values are multiplied digit group by digit group, so no digits are lost.

How to use the Factorial Calculator

  1. Enter the whole number n you want to use.
  2. Choose a single factorial or a double factorial.
  3. Press Calculate to see the exact value, its digit count and scientific form.

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Frequently Asked Questions

Common questions about the free online factorial calculator.

Enter a whole number, choose n! or n!! and press Calculate. The exact value appears with its digit count and scientific form.
The factorial of n multiplies every whole number from 1 up to n, so 5! equals 1 x 2 x 3 x 4 x 5, which is 120.
The double factorial steps down by two, so 6!! is 6 x 4 x 2, which equals 48, and 7!! is 7 x 5 x 3 x 1, which is 105.
By convention the empty product is one, and that definition keeps formulas such as the binomial coefficient working.
Ordinary factorials are calculated exactly up to 170!, while double factorials stay exact up to 300!! in this tool.
They are exact. The tool multiplies digit groups directly instead of using floating point, so no digits are lost.
170! is 309 digits long, and the result panel wraps long values while the scientific line keeps them readable.
No. Every factorial is computed inside your browser and no value you enter leaves your device.

Last updated: October 10, 2026