Factorial Calculator
Compute n! (factorial) and related values.
Input Data
Full factorial or falling product.
N
K
Results
Computed factorial/product.
120
Explanatory note about the result.
5! = 120
At a glance:n! = n·(n−1)·…·1 (0! = 1). Falling product n·(n−1)·…·(n−k+1). Complements combination and permutation.
Formula
n! = ∏_{i=1}^{n} i.
How to Use
- Enter n (and k for mode).
- The tool returns the product.
Case Studies
5!
120.
FAQ
What is 0!?
Defined as 1, for combinatorial consistency.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.