Understand the subject
What is a permutation with repetition?
This counts ordered strings when each position may reuse any available symbol. Each new position starts with the full set of choices again.
Use it for codes, repeated draws with replacement, and ordered symbol strings.
See the structure
Every position receives the full choice set
start↙ ↓ ↘10 choices10 choices10 choices10 choices10⁴ = 10,000
Worked example
Check the rule with a small case
Four digit strings allow 10⁴ = 10,000 outcomes, including leading zeroes.
Interpret with care
Choose the right counting model
If a symbol cannot repeat, use the ordinary permutation model.
Use the Permutation & Combination Generator when a small case needs to be inspected rather than only counted.
Quick guide
How to use this calculator
- Enter the number of available symbols n.
- Enter the number of ordered positions r.
- Read the exact number of strings.
Calculation method
Apply the product rule to every position
Each of r positions independently has n choices, so the count is n raised to r.
Worked example
Four-digit strings
Ten digits may be reused in each of four positions.
10⁴ = 10,000
Supported inputs
Precision and limits
Discrete domain
Inputs are whole counts. Negative, fractional, grouped, and scientific-notation inputs are rejected.
Exact integers
Results use arbitrary-precision integers and are never rounded. Inputs and output size are bounded to keep the page responsive.