Permutation Calculator — nPr (Ordered Arrangements)

Count ordered arrangements nPr when rank, sequence, or podium order matters—distinct from combinations where AB equals BA.

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nPr counts ordered arrangements: how many ways to fill r distinct positions from n items when order matters and (usually) items are not reused. 10P3 = 10×9×8 = 720 podium orderings.

10P3 = ?

10 × 9 × 8 = 720 (order matters)

nPr vs nCr?

nPr counts order; nCr ignores it — see comparison below

With repetition?

Use n^r mode when items can repeat (e.g. 10^3 PINs)

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By Muhammad Abdullah Rauf · Founder, EverydayTools.proUpdated 2026-07-03· Reviewed by EverydayTools Editorial Team

What does nPr count in combinatorics?

Permutations answer ranking problems. Gold, silver, and bronze among 10 sprinters: first place has 10 choices, second has 9, third has 8—10P3 = 720 distinct medal tables where order matters.

Swap two medalists and you get a different permutation. If order were irrelevant, you would use combinations (nCr) instead—same three athletes, one unordered trio.

Formula: nPr = n! / (n−r)! = n × (n−1) × … × (n−r+1)—only r descending factors, not the full factorial. When r = n, nPn = n! (every ordering of all items).

**With repetition** (each slot can reuse items), the count is n^r—different model from standard nPr. A three-digit PIN with digits 0–9 allowing repeats has 10³ = 1,000 codes, not 10P3 = 720.

This calculator uses exact big integers for modest n—critical when homework expects 26P3 = 17,576 exactly, not rounded scientific notation.

Order matters → nPr. Enter n and r for exact nPr, or switch to n^r mode when slots can repeat.

Quick answers

Concise answers for common searches — definitions, steps, and comparisons.

What is 10P3?

10P3 = 10×9×8 = 720 ordered selections of three items from ten.

Permutation vs combination in one line?

Permutation: order matters (ABC ≠ BAC). Combination: order ignored—same letters, one group.

What is nP0?

nP0 = 1 for any n ≥ 0. There is exactly one empty arrangement.

When do you use n^r instead of nPr?

When each of r positions can reuse the same item—like a 4-digit PIN with repetition allowed.

Permutation formula

Standard mode computes nPr = n!/(n−r)! with BigInt factorials. Repetition mode computes n^r when each of r positions has n choices independently.

Formula

Without repetition: nPr = n!/(n−r)! for 0 ≤ r ≤ n. With repetition: arrangements = n^r. Relation: nCr = nPr / r!.

Assumptions

  • Items are distinguishable unless stated otherwise.
  • Without-replacement model: each item used at most once per arrangement.

Limitations

  • Does not handle circular permutations (necklaces) or identical objects—those need specialized formulas.
  • n capped for exact display in browser—very large n may hit practical limits.

How to use Permutation Calculator — nPr (Ordered Arrangements)

  1. Confirm order matters

    If swapping two chosen items changes the outcome, permutations apply. Committees without roles use combinations.

  2. Enter n and r

    n is pool size; r is how many ordered slots you fill. Require 0 ≤ r ≤ n in no-replacement mode.

  3. Pick repetition mode if needed

    When digits or letters can repeat, use n^r—not standard nPr.

  4. Compare to nCr

    Divide nPr by r! to get combinations when order should not matter.

Permutation Calculator — nPr (Ordered Arrangements) examples

Textbook starter

Input

n = 5, r = 2

Output

5P2 = 20

5×4 = 20 two-letter codes without repeated letters.

Podium

Input

n = 10, r = 3

Output

10P3 = 720

Medal order matters—720 distinct top-three lists.

Full shuffle

Input

n = 6, r = 6

Output

6P6 = 6! = 720

Every ordering of six distinct cards.

Edge r = 0

Input

n = 9, r = 0

Output

9P0 = 1

One way to arrange zero items—the empty selection.

Alphabet codes

Input

n = 26, r = 3

Output

26P3 = 17,576

26×25×24—no repeated letters in three positions.

With repetition contrast

Input

n = 10, r = 3, digits repeat

Output

10³ = 1,000 (not 720)

PIN model allows 000—permutation without repeat undercounts.

When to use a permutation calculator

Common real-world scenarios where this tool saves time.

Sports podium counts

Top three from eight finalists: 8P3 = 8×7×6 = 336 distinct medal orderings.

License plates or codes without repeat

Three letters from A–Z, no letter twice: 26P3 = 17,576 sequences.

Seating charts with assigned seats

Pick and order 4 people for 4 labeled chairs from 12 candidates: 12P4.

Password policy modeling (simplified)

Eight unique characters chosen in order from a charset—permutation with r = 8 when reuse is forbidden.

Workflow guides

Step-by-step chains that connect related tools for common tasks.

Related mathematical concepts

  1. Combinations nCr = nPr / r! remove order from the same selection pool.
  2. Factorials underpin nPr via cancellation of (n−r)! terms.
  3. Probability divides favorable permutations by total nPr when outcomes are equally likely and ordered.
  4. Multiset and circular permutations adjust the basic nPr when symmetry or duplicates appear.

Reference tables

Ordered vs unordered selection

ScenarioTool5 pick 2Why
President & VPnPr20Roles differ
Committee of 2nCr10Same pair either order
3-digit PIN, repeatn^r1000Slots independent
3-letter code, no repeatnPr60 (from 5)5P3 example

Common nPr anchors

NotationValueContext
5P220Intro drills
8P3336Sports podium
26P317,576Letter codes
nPnn!Full permutations

Best practices

Multiply r factors instead of full factorials

10P3 = 10×9×8 avoids computing 10! and 7! separately on paper.

Sanity-check against n^r

nPr ≤ n^r always. Equality only when r = 1 or n is tiny with special cases.

Link to factorial tool for nPn

When r = n, verify n! on the factorial calculator.

Halve with nCr when order drops out

If problem text says “committee” or “hand,” switch tools before computing.

Common mistakes to avoid

Using nCr for ranked outcomes

Medals and permutations of letters in a word need nPr. nCr divides out order.

Allowing r > n in no-replacement mode

You cannot pick more distinct items than exist—r must be ≤ n.

Applying nPr when repetition is allowed

Independent slots use n^r. nPr assumes no reuse.

Treating identical objects as distinct

BOOK has duplicate letters—multiset permutations need factorial division by duplicate counts, not raw nPr.

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Frequently Asked Questions

How is 7P2 calculated by hand?

7P2 = 7×6 = 42. Multiply two descending factors starting at 7.

Can permutations include duplicates in the pool?

Standard nPr assumes distinct items. Duplicate letters need adjusted formulas dividing by factorials of repeat counts.

What is a circular permutation?

Rotations of a necklace count as one arrangement: (n−1)! for n distinct beads. This tool uses linear nPr.

Why is nPr always divisible by r!?

Because nCr = nPr/r! is always an integer—combinations count unordered subsets.

Does 0P0 equal 1?

Yes—empty arrangement convention matches 0! = 1.

How do permutations enter probability?

If each ordered outcome is equally likely, probability of one specific ordering is 1/nPr.

What is the largest n this tool supports?

Exact bigint nPr is supported for n up to 500 in standard mode—sufficient for coursework.

Privacy, accuracy, and trust

Privacy

n and r stay in your browser for local calculation.

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Reviewed by EverydayTools Editorial Team on 2026-07-03.

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