Factorial Calculator
Calculate factorials (n!), permutations (nPr), and combinations (nCr). Supports ...Calculate factorials (n!), permutations (nPr), and combinations (nCr). Supports very large numbers with BigInt.
Factorial Reference (n!)
When to Use Each
Total ways to arrange ALL n items. Example: 5 people in a line = 5! = 120 arrangements.
Arrangements where ORDER MATTERS. Example: Gold/Silver/Bronze from 10 athletes = P(10,3) = 720.
Selections where ORDER DOESN'T MATTER. Example: Choose 3 from 10 for a team = C(10,3) = 120.
Calculator Features
Why Use Factorial Calculator?
Three Calculations in One
Calculate factorials (n!), permutations (nPr), and combinations (nCr) in one tool.
BigInt Support
Calculate factorials up to 10,000 using JavaScript BigInt for unlimited precision.
Step-by-Step Breakdown
See the multiplication steps for small factorials to understand the calculation.
Formula Display
View the mathematical formula being used for each calculation type.
Copy Large Results
Copy results with thousands of digits to clipboard for use elsewhere.
100% Private
All calculations happen in your browser. No data sent to servers.
Common Uses
Probability
Calculate the number of ways events can occur in probability problems.
Combinatorics
Count arrangements and selections in discrete mathematics.
Statistics
Used in binomial distributions, permutation tests, and sampling.
Computer Science
Algorithm analysis, sorting complexity, and graph theory.
How It Works
Choose Calculation Type
Select Factorial (n!), Permutation (nPr), or Combination (nCr) based on your needs.
Enter Your Values
Input n (and r if using permutations or combinations). Max n is 10,000.
View the Formula
See the mathematical formula being applied to your values.
Get Your Result
See the result with digit count. Copy large numbers to clipboard if needed.
Math Tips
Factorials Grow Fast
10! = 3.6 million, 20! = 2.4 quintillion. Factorials grow extremely fast - that's why BigInt is needed.
nCr vs nPr
Use nPr when order matters (podium positions). Use nCr when order doesn't matter (team selection).
Copy Large Results
Results with 50+ digits are truncated for display. Use the Copy button to get the full number.