# Permutation Calculator

> Calculate P(n, r) for arrangements where order matters. Supports without-repetition and with-repetition modes.

**URL:** https://www.calculatoranswers.com/permutation-calculator
**Category:** Education

## Quick Answer

Calculate the number of unique arrangements for a set of items where order matters. Enter the total items and number to select.

## Definition

A permutation calculator computes the number of unique ways to arrange a subset of items selected from a larger set where the order of selection is significant. It calculates both permutations without repetition, using the formula P(n, r) = n! / (n-r)!, and permutations with repetition, using n^r. Statisticians, computer scientists, and combinations planners use this calculation to solve combinatorial problems, analyze security passcode possibilities, and determine potential sequences in probability experiments.

## How to Use

1. **Select repetition mode** — Choose whether items can be repeated or if each item must be unique.
2. **Enter total items (n)** — Type the total number of items in the set into the first field.
3. **Enter items to select (r)** — Input the number of items to be selected and arranged.
4. **Read arrangements count** — View the total number of permutations along with the formula and mathematical steps.

## Disclaimer

This calculator provides estimates for educational and planning purposes. Always consult a qualified professional for specific advice on financial, medical, legal, or other regulated decisions.

---

*This page is part of Calculator Answers — simple calculators, clear answers, no signup required. View all calculators at https://www.calculatoranswers.com/calculators*