Back to Free Tools
FREE TOOLS
Exact Factorial and Combinatorics Calculator
Calculate exact factorial, double factorial, derangement, permutation or combination counts.
Admitted integer or rational text fields
combinatorics.json
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the admitted values using the labeled input fields.
- Choose the explicit operation and options, then inspect the stated conventions and limits.
- Select Calculate exact count and download combinatorics.json.
Examples
10 choose 3 is 120; 0! and 0!! are 1.
Limitations
- Unsigned ASCII integer n 0–1,000; selected r 0–n, at most 4 token digits. A 64 KiB complete report and30-second limit apply. Gamma values, negative factorials and replacement counting are outside scope.
Related tools
No items found.