Understand the subject
What is a permutation?
A <strong>permutation</strong> is an ordered selection. The same objects placed in a different order create a new outcome.
Use it for rankings, podium places, PIN positions, and ordered assignments without repetition.
See the structure
Positions make order matter
1st: A, 2nd: B1st: B, 2nd: Adifferent outcomes
Worked example
Check the rule with a small case
Award gold, silver, and bronze among 10 people: P(10,3) = 10 × 9 × 8 = 720.
Interpret with care
Choose the right counting model
Do not divide by r factorial when roles or positions make order meaningful.
Use the Permutation & Combination Generator when a small case needs to be inspected rather than only counted.
Quick guide
How to use this calculator
- Enter the total number of distinct objects n.
- Enter the number of ordered positions r.
- Read the exact number of ordered selections.
Calculation method
Fill each ordered position
There are n choices for the first position, n−1 for the second, and so on for r positions.
Worked example
Award three places among ten people
First, second, and third place are different roles, so order matters.
P(10,3) = 10!/7! = 720
Supported inputs
Precision and limits
Discrete domain
Inputs are whole counts. Negative, fractional, grouped, and scientific-notation inputs are rejected.
Exact integers
Results use arbitrary-precision integers and are never rounded. Inputs and output size are bounded to keep the page responsive.