CalmCalc
MATH

Permutation and Combination Calculator

Estimate combinations from total amount in a set, amount in each sub-set with the Permutation and Combination Calculator.

How are selections counted?Choose whether order matters and whether an item may be selected more than once.
3 options
COMBINATIONS120

Exact integer result computed without floating-point rounding.

Permutations (nPr)
720
Combinations (nCr)
120
Estimate based on the values shown
MethodUses nCr when order does not matter, nPr for ordered selections without reuse, and n^r for ordered selections with repetition.

Before you use the result

The result depends on the entered values, selected mode, and displayed mathematical assumptions.

CALCULATOR GUIDE

How to use the Permutation and Combination Calculator

Estimate combinations from total amount in a set, amount in each sub-set with the Permutation and Combination Calculator. It includes Combination, Permutation, Permutation with repetition workflows, so choose the one that matches the values you actually know. Use it to check the arithmetic while keeping the displayed method and entered values with your work.

Step by step

  1. For the Permutation and Combination, enter total amount in a set, amount in each sub-set. Keep each value in the unit displayed beside its field.
  2. Review the selected Permutation and Combination workflow and inputs, then read combinations in the result panel.
  3. Change one Permutation and Combination assumption at a time to compare scenarios. Use Reset to restore this tool's worked example values.

How the calculation works

Uses nCr when order does not matter, nPr for ordered selections without reuse, and n^r for ordered selections with repetition.

Worked example

In the Permutation and Combination worked example, total amount in a set 10, amount in each sub-set 3 produces combinations of 120. Exact integer result computed without floating-point rounding. Review the displayed units before comparing the result.

Understanding the result

The Permutation and Combination reports combinations. Use it to check the arithmetic while keeping the displayed method and entered values with your work. The result depends on the entered values, selected mode, and displayed mathematical assumptions.

How to check the answer

Check the Permutation and Combination answer by substituting combinations back into the stated relationship. Test a simple value such as zero, one, or an equal pair, then confirm that sign, scale, units, and rounding match Uses nCr when order does not matter, nPr for ordered selections without reuse, and n^r for ordered selections with repetition.

Common questions

What does the Permutation and Combination calculate?

Estimate combinations from total amount in a set, amount in each sub-set with the Permutation and Combination Calculator.

Which Permutation and Combination inputs have the biggest effect?

combinations responds directly to total amount in a set, amount in each sub-set. Change one input while holding the others constant to see its effect.

Is the Permutation and Combination result exact?

The result depends on the entered values, selected mode, and displayed mathematical assumptions. Recheck total amount in a set, amount in each sub-set and use combinations only for a decision where that level of precision is appropriate.

Formula tests, limits, sources, and guide registry updated September 1, 2026.
INTERPRET THE RESULTRead the math guideCheck assumptions, limitations and comparison methods →