Formula and calculation method
Permutations = n!/(n−r)!. Combinations = permutations/r!.
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
How to use permutation and combination calculator
- Set Total items n. The example below uses 10.
- Set Chosen items r. The example below uses 3.
- Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.
Worked example
Example inputs
- Total items n
- 10
- Chosen items r
- 3
- Permutations
- 720
- Combinations
- 120
Factors affecting your result
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Changing total items n changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.
Frequently asked questions
How does the permutation and combination calculator work?
Permutations = n!/(n−r)!. Combinations = permutations/r!.
What inputs does Permutation and Combination Calculator need?
Enter total items n, chosen items r. Choose values that correspond to the same situation and measurement convention.
How should I interpret the permutation and combination calculator result?
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Are my permutation and combination calculator inputs uploaded?
No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.
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