Permutation and Combination Calculator

Calculate permutations (nPr) and combinations (nCr) for probability and counting problems. Use this math calculator online for fast, accurate results.

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About this Permutation and Combination Calculator

Permutations and combinations count the number of ways items can be arranged or selected from a larger set. This Permutation and Combination instantly calculates both values, saving you from manually multiplying out factorials, which grow extremely large and error-prone even with modestly sized sets.

What is Permutation and Combination?

A Permutation and Combination Calculator applies a fixed mathematical formula to the values you provide and returns the exact result, with no rounding shortcuts or manual arithmetic involved.

Where doing this by hand leaves room for a misplaced decimal, a dropped sign, or a skipped step, the calculator applies the same rule every single time, so the answer is only ever as good as the numbers you put in.

This makes it useful both for checking your own work and for quickly getting an answer when you already understand the concept but do not want to spend time on the mechanical part.

Reading Your Results

Your result shows both the permutation and combination totals for your chosen n and r values. Use permutations when the arrangement order matters, such as ranking winners, and combinations when only the selected group matters, such as choosing a committee.

How to use this calculator

1Enter the total number of items (n).
2Enter the number of items being chosen (r).
3Select whether order matters (permutation) or not (combination).
4Click "Calculate."

The calculator determines the number of possible permutations or combinations.

Permutations: P(n, r) = n! ÷ (n − r)!
Combinations: C(n, r) = n! ÷ (r! × (n − r)!)
Factorial: n! = n × (n − 1) × (n − 2) × ... × 1

Where

n = Total number of items
r = Number of items selected
0! = 1 by definition

Example

Total Items (n) = 5
Items Chosen (r) = 3
Permutations = 5! ÷ (5 − 3)! = 120 ÷ 2 = 60
Combinations = 5! ÷ (3! × 2!) = 120 ÷ 12 = 10
How the Permutation and Combination Calculator Works 1. Enter Values Type in your Permutation and Combination inputs into the form. 2. Calculation Engine The calculator applies the correct formula instantly. 3. Your Result View your accurate Permutation and Combination result instantly. No sign-up needed. Adjust any input and recalculate as many times as you like.

Factors Affecting Your Permutation and Combination Result

The result here depends entirely on the specific values you enter, since the underlying formula itself does not change. What does vary is how sensitive the outcome is to each input: in some formulas, one variable dominates the result almost entirely, while in others, every input contributes roughly equally.

Rounding at intermediate steps, using the wrong unit for an input, or transposing two values are the most common reasons a manually calculated answer differs from what this tool returns, so it is worth double-checking your inputs first if a result looks unexpected.

Benefits of Using the Permutation and Combination Calculator

  • Handles large factorials instantly, which quickly become impractical to calculate by hand.
  • Clearly separates order-sensitive permutations from order-independent combinations.
  • Useful for statistics, probability, and combinatorics coursework.

Frequently asked questions

What is the difference between permutations and combinations?

Permutations count arrangements where order matters, such as race rankings. Combinations count selections where order does not matter, such as choosing a team.

What does 0! equal?

By mathematical convention, 0! (zero factorial) equals 1.

Can r be larger than n?

No, you cannot select or arrange more items than exist in the original set, so r must be less than or equal to n.

Does this work with negative numbers?

This depends on the specific operation. Some mathematical operations, like even-numbered roots of negative numbers, produce complex (non-real) results, which this calculator will flag accordingly.

How precise are the results?

The calculator returns results to several decimal places for maximum precision, though you can round to fewer decimal places depending on what your specific use case requires.

Final Words

While the Permutation and Combination Calculator is an incredibly efficient tool for quick estimates and preliminary planning, it relies entirely on the accuracy of the base figures you provide. Real-world applications often involve subtle nuances that a rigid digital formula might miss.

We strongly encourage you to cross-reference these automated metrics with accredited professionals or official documentation to ensure total accuracy.

Disclaimer

This calculator provides estimates for general informational and educational purposes only and should not be treated as financial, medical, legal, or professional advice. Results depend entirely on the accuracy of the figures you enter.

Always verify important decisions with a qualified professional, official documentation, or your financial institution before acting on any result shown here.

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