String Permutations and Combinations

Features

• Five modes: permutations, combinations of k, left and right rotation, cartesian product
• ⚠️ Exact count first, then generate — over the limit it errors, never truncates silently
• Duplicate characters removed: aab yields 3 permutations, not 6
• Combinations counted exactly via generating-function coefficients
• Choose generation order or sorted output
• Reports the result count and the current limit
• Code-point based, so emoji are never split

How to use

1. Enter one line of text
2. Pick a mode; for combinations set k
3. Adjust deduplication, order and the limit as needed
4. The result list and count appear immediately

FAQ

Why an error instead of the first 1000 results?

Silent truncation makes it look like “that is all there is”. Permutation counts grow factorially, and the missing results are often the ones you were looking for, so it says how many are needed instead.

How are duplicate characters handled?

Generation walks a per-character count rather than swapping positions, so two identical letters are never treated as two results. That is why `aab` gives 3.

How do I enter a cartesian product?

Separate the groups with commas; each group contributes its characters. `ab,12` gives a1, a2, b1, b2.

Is anything uploaded?

No. It is all computed in memory in your browser, no request is made, and it works offline.