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  1. Home
  2. Math Calculators
  3. Permutations with Replacement Calculator

Permutations with Replacement Calculator

Calculate permutations with replacement (n^r) - arrangements where items can be repeated and order matters. Perfect for PIN codes, passwords, and lock combinations.

Formula:PR(n,r) = nʳ

Results

Permutations

10,000

10^4

n (options per position)10
r (positions/length)4
Time to guess (1000/sec)10 seconds
Without replacement5,040

Input Values

Number of choices at each position

Length or number of selections

Show P(n,r) without replacement

Results

With Replacement

Arrangements where items can repeat

10,000

10^4

Security Estimate

Time to try all combinations

10 seconds

at 1,000 attempts/second

With Replacement (n^r)

10,000

Without Replacement (n!/(n-r)!)

5,040

Ratio: 1.98x more with replacement

Step-by-Step Calculation

Step 1:PR(10, 4) = 10^4
Step 2:PR(10, 4) = 10 x 10 x ... (4 times)
Step 3:PR(10, 4) = 10 x 10 x 10 x 10
Step 4:PR(10, 4) = 10,000

Visual Representation

10
Pos 1
10
Pos 2
10
Pos 3
10
Pos 4

Each position has 10 choices = 10^4 = 10,000 total

Practical Examples

Click to calculate:

Password Strength Guide

Character Setn6 chars8 chars12 chars
Digits only (0-9)101M100M1T
Lowercase (a-z)26309M209B95Q
Mixed case (a-z, A-Z)5219B53T390Sx
Alphanumeric6257B218T3.2Sx
All printable95735B6.6Q540Sx

M = Million, B = Billion, T = Trillion, Q = Quadrillion, Sx = Sextillion

Permutations Comparison

TypeOrderReplacementFormulaResult
PR (this)YesYesn^r10,000
P (standard)YesNon!/(n-r)!5,040
CRNoYesC(n+r-1, r)-
C (standard)NoNon!/(r!(n-r)!)-

Formula Reference

Permutations with Replacement

PR(n, r) = n^r

Order: Yes | Replacement: Yes

Standard Permutations

P(n, r) = n!/(n-r)!

Order: Yes | Replacement: No

Results

Permutations

10,000

10^4

Time to guess10 seconds

Common Permutation Examples

Quick-start with common scenarios

Practice Permutation Problems

Test your skills with practice problems

Practice with 4 problems to test your understanding.

?How Do You Calculate Permutations with Replacement?

Permutations with replacement count arrangements where items CAN be repeated and order MATTERS. Formula: PR(n,r) = n^r. Example: 4-digit PIN from digits 0-9 = 10^4 = 10,000 possible codes. Each position has n choices, and we have r positions, giving n x n x ... x n = n^r total arrangements.

What are Permutations with Replacement?

Permutations with replacement count the number of ways to arrange r items from n types where each item can be used multiple times and the order matters. The formula PR(n,r) = n^r comes from having n choices for each of r positions. Common examples include PIN codes (each digit 0-9 can repeat), passwords (letters/numbers can repeat), and combination locks (each dial has same options).

Key Facts

  • Permutations with replacement allow using the same item multiple times
  • Formula: PR(n,r) = n^r (n to the power of r)
  • Order MATTERS: 1234 is different from 4321
  • Each position has n independent choices
  • Used for: PIN codes, passwords, license plates, phone numbers
  • 4-digit PIN (0-9): 10^4 = 10,000 combinations
  • 6-character password (a-z): 26^6 = 308,915,776 combinations
  • Always larger than permutations without replacement when r > 1

Quick Answer

Permutations with replacement count arrangements where items CAN be repeated and order MATTERS. Formula: PR(n,r) = n^r. Example: 4-digit PIN from digits 0-9 = 10^4 = 10,000 possible codes. Each position has n choices, and we have r positions, giving n x n x ... x n = n^r total arrangements.

Frequently Asked Questions

Permutations with replacement count arrangements where items CAN be repeated and order MATTERS. For example, in a 4-digit PIN, each digit can be 0-9 (repeated), and 1234 is different from 4321. Formula: PR(n,r) = n^r.

Arrangements where items can repeat and order matters. PR(n,r) = n^r.

With digits 0-9 (10 options) and 4 positions: 10^4 = 10,000 possible PINs. Each position has 10 choices, and digits can repeat. At 1 guess per second, it takes ~2.8 hours to try all combinations.

10^4 = 10,000 possible 4-digit PINs using digits 0-9.

The formula is PR(n,r) = n^r (n to the power of r). This represents n choices for each of r positions, all independent of each other. The formula works because each position multiplies the total by n options.

PR(n,r) = n^r. Each of r positions has n independent choices.

WITH replacement: items can repeat, formula is n^r. WITHOUT replacement: items cannot repeat, formula is n!/(n-r)!. Example: 4-digit PIN with repeats = 10^4 = 10,000. Without repeats = 10!/6! = 5,040.

With: n^r (items can repeat). Without: n!/(n-r)! (no repeats allowed).

Password strength depends on character set (n) and length (r). Lowercase only (26^r): 6 chars = 309M. Add uppercase (52^r): 6 chars = 19B. Add digits (62^r): 6 chars = 57B. Add symbols (95^r): 6 chars = 735B combinations.

More characters and longer length exponentially increase security. 8+ characters with mixed types recommended.

Last updated: 2025-01-15

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Results

Permutations

10,000

10^4

n (options per position)10
r (positions/length)4
Time to guess (1000/sec)10 seconds
Without replacement5,040