Factorial Calculator
The factorial of a non-negative integer n, written n!, is the product of every positive integer from 1 to n (with 0! defined as 1). Factorials grow extremely fast — 20! already has 19 digits — so Toolverge uses exact BigInt arithmetic instead of regular floating-point numbers, which lose precision past 2^53. The display is capped at 170! for a responsive page, though the same BigInt math supports much larger values.
How it works
- Enter a non-negative integer.
- The calculator multiplies 1 through n using exact BigInt math.
- The result and its digit count are shown; display is capped at 170! for performance.
Formula n! = n × (n-1) × (n-2) × ... × 1, with 0! = 1
Frequently asked questions
What is 5 factorial?
5! = 5 × 4 × 3 × 2 × 1 = 120.
What is 0 factorial?
0! is defined as 1 by convention.
Why use BigInt instead of a normal number?
Factorials exceed the safe integer range very quickly; BigInt keeps every digit exact instead of rounding.
Can factorial be negative?
No. Factorial is only defined for non-negative integers.
Why is the display capped at 170?
170! is roughly the largest factorial a standard double can represent; the calculator caps display there for speed, though its BigInt math itself has no such limit.