# Permutation Calculator

> Calculate Permutations (nPr) and Combinations (nCr).

Page: https://askcalculators.com/calculator/permutation-calculator/
Definition: https://askcalculators.com/calculator/permutation-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/permutation-calculator/schema.json
Version: 7.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/permutation-calculator/?n=10&r=3

## Inputs
- n: Total Items (n); type=number; optional; default=10
- r: Items to Choose (r); type=number; optional; default=3

## Outputs
- result: Result; format=text; primary

## Formula
Permutations nPr = n! ÷ (n−r)!; combinations nCr = n! ÷ [r!(n−r)!].

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.