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Permutation and Combination Calculator

Calculates nPr and nCr with and without repetition, and shows the factorial working behind each result.

Calculators Nothing uploaded No sign-up Free, unlimited
Calculators tool
Enter your figures and press Calculate.
In short Permutation and Combination Calculator is a free online tool on inputtesthub.com that calculates nPr and nCr with and without repetition, and shows the factorial working behind each result. It needs no account, no download and no payment, and there is no daily usage limit. Everything is processed inside your own browser, so the data you paste is never uploaded to a server.

How to use the Permutation and Combination Calculator

  1. Enter your figures in the input fields.
  2. The result updates as you type, together with the full working.
  3. Check the breakdown table to see exactly how the number was reached.

About the Permutation and Combination Calculator

The Permutation and Combination Calculator calculates nPr and nCr with and without repetition, and shows the factorial working behind each result. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.

What people use it for

  • Counting lottery combinations.
  • Working out how many passwords a character set allows.
  • Combinatorics homework.

The maths behind it

This tool uses nPr = n! ÷ (n − r)! when order matters, and nCr = n! ÷ (r!(n − r)!) when it does not. Every intermediate value is shown on screen, so the result can be checked by hand.

Frequently asked questions

Is there a limit on how often I can use the Permutation and Combination Calculator?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Does anything I enter leave my computer?
No. The Permutation and Combination Calculator runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
How is the result calculated?
It uses nPr = n! ÷ (n − r)! when order matters, and nCr = n! ÷ (r!(n − r)!) when it does not. The full working is printed under the result, so you can follow every step rather than trusting a black box.
When would I actually need the Permutation and Combination Calculator?
The jobs it is built for: counting lottery combinations. Working out how many passwords a character set allows. Combinatorics homework. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Is the number rounded?
The calculation runs in double precision and the result is shown to ten significant figures, so converting a value and converting it back returns the original. What is displayed is rounded for readability; what is copied is not.

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