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Free Online Factorial Calculator

Calculate exact factorials using arbitrary-sized integers.

Your input stays on this device. Processing is bounded; regex runs in a worker with a two-second timeout.

Result



How to use Factorial Calculator
Calculate exact factorials using arbitrary-sized integers. BigInt provides exact integer results for 0–2,000. Both 0! and 1! equal 1; non-integers and negative inputs are rejected.
  1. Set Number.
  2. Run the tool, review the result and its stated limitations, then copy or download if needed.
Example & practical use
Calculate exact factorials using arbitrary-sized integers. The example below demonstrates Number.
Example input:
{
  "a": 10
}
Expected result (relevant fields):
{
  "result": "3628800"
}
Features & result limitations
BigInt provides exact integer results for 0–2,000. Both 0! and 1! equal 1; non-integers and negative inputs are rejected.
Frequently asked questions
What inputs does Factorial Calculator accept?
Number
How should I interpret the Factorial Calculator result?
BigInt provides exact integer results for 0–2,000. Both 0! and 1! equal 1; non-integers and negative inputs are rejected.
Where does Factorial Calculator process my data?
Inputs are processed locally in your browser. Submitted text is not sent to external services. A successful-run event increments an aggregate tool counter without your input.