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Updated 2026-03-07 UTC
Permutation Calculator — nPr with Examples
Compute permutations (nPr): the number of ordered selections. Includes examples, verification tips, and common mistakes — powered by GetCalcMaster.
Permutations count **ordered** selections. If order matters (e.g., podium finishes), you want permutations (nPr), not combinations (nCr).
Important: This content and tool are for educational purposes only. Outputs are estimates; always cross‑verify with official sources and/or a qualified professional.
What this calculator is
The Scientific Calculator is an interactive tool inside GetCalcMaster. It’s designed to help you explore scenarios, understand formulas, and document assumptions.
Key features
- Immediate results as you change inputs
- Transparent assumptions and explainable outputs
- Works well with the built‑in Notebook for saving scenarios
Formula
nPr = n! / (n−r)! (for integers n≥0, 0≤r≤n)Quick examples
npr(10, 3) # 720npr(5, 2) # 20# Identity check: nPr = nCr × r! ncr(10, 3) * factorial(3)
Verification tips
- Quick check: npr(n, 1) = n and npr(n, n) = n!.
- Identity: nPr = nCr × r! (when both are defined).
- If r>n, the answer should be 0 in many conventions (or ‘not defined’).
Common mistakes
- Using permutations when order doesn’t matter (you probably want combinations).
- Swapping n and r.
- Forgetting that r must be ≤ n in the standard definition.
How to use it (quick steps)
- Decide how many items you have (n) and how many you pick (r).
- Open the Scientific Calculator.
- Enter npr(n, r) (or nPr) to compute the number of ordered selections.
- Verify with a small case by listing possibilities or using factorial identities.
- If order does *not* matter, use combinations (nCr) instead.
Related tools and guides
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Scientific calculator guide
Scientific workflows and key functions.
Trigonometry workflow
sin/cos/tan with unit checks.
Logarithms workflow
ln, log10, and change-of-base.
Math hub
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FAQ
What’s the difference between permutations and combinations?
Permutations care about order (ABC ≠ ACB). Combinations ignore order (ABC = ACB).
What does nPr mean?
‘Number of ways to choose r items from n, where order matters.’
How do I compute nPr quickly?
Use npr(n,r) or the factorial formula n!/(n−r)!.
Tip: For reproducible work, save your inputs and reasoning in Notebook.