Last Updated: April 13, 2026
Permutation & Combination Calculator
Free permutation and combination calculator. Calculate nPr and nCr for probability and counting.
Permutation P(n,r)
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Combination C(n,r)
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n!
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r!
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📐 How We Calculate — Learn about our calculation methodology, data sources, and quality standards.
Frequently Asked Questions
Permutation vs combination?
Permutation: order matters (ABC ≠ BCA). Combination: order doesn't matter (ABC = BCA).
When to use each?
Use permutation for rankings, arrangements, passwords. Use combination for teams, groups, lottery.
What does n! mean?
n factorial = n × (n-1) × (n-2) × ... × 1. Example: 5! = 120.