Isograms: words with no repeated letter
An isogram is a word with no repeated letter — every letter used exactly once. 34,758 of the 168,401 words in our dictionary qualify, 20.6% of the whole list.
How common they are, by length
Short words are almost automatically isograms; long ones have to work for it, because every extra letter is another chance to repeat one already used:
| Length | Isograms |
|---|---|
| 2 letters | 94 |
| 3 letters | 868 |
| 4 letters | 3,091 |
| 5 letters | 5,651 |
| 6 letters | 7,246 |
| 7 letters | 7,651 |
| 8 letters | 5,840 |
| 9 letters | 2,784 |
| 10 letters | 1,094 |
| 11 letters | 348 |
| 12 letters | 72 |
| 13 letters | 14 |
| 14 letters | 3 |
| 15 letters | 2 |
The longest isograms in our list
Our dictionary is capped at 15 letters, and exactly 2 words that long avoid repeating a single letter:
Both are genuine, specific words: one is the study of fingerprint and skin-ridge patterns, the other describes something that cannot legally be copyrighted. Past that length our dictionary has nothing to say — longer English isograms may well exist.
Common isograms
3,326 isograms are common, everyday words — 41.0% of our entire common-word list. Avoiding a repeated letter turns out to be closer to luck than rarity: plenty of ordinary words simply never repeat one. A sample, most frequent first:
Broken down by length, common isograms cluster shorter than isograms overall — unsurprising, since short words are common far more often than long ones:
| Length | Common isograms |
|---|---|
| 2 letters | 84 |
| 3 letters | 341 |
| 4 letters | 746 |
| 5 letters | 817 |
| 6 letters | 629 |
| 7 letters | 386 |
| 8 letters | 195 |
| 9 letters | 94 |
| 10 letters | 26 |
| 11 letters | 8 |
Where isograms peak
The single length with the most isograms is 7 letters, holding 7,651 of them — roughly the same stretch of the dictionary that holds the bulk of every word overall, as our word-count guide sets out length by length. Past that point, avoiding a repeat gets steadily harder as there are more positions for a letter to collide with one already used.
A sample at the peak
Isograms at 7 letters, the length with the most of any in our dictionary:
The Wordle angle
65.6% of the 8,610 five-letter words in our five-letter word list are isograms, leaving 34.4% with a letter repeated at least once. A guess with a repeated letter is already working against those odds.
The opposite extreme
At the other end sit words that lean hardest on a small handful of letters — the fewest distinct letters possible stretched across the most positions. Ranking every word of six or more letters by that ratio of distinct letters to length, the most repetitive in our dictionary are:
The most extreme reuses just 4 distinct letters across its 15.
Why players care
A rack with no repeated letter is free to attempt an isogram without working around a duplicate tile, which is one reason the sample above is worth knowing for Scrabble as much as for word puzzles — see our best Scrabble words guide for how face value is worked out at every length.
Elsewhere on the site
Isograms matter most for Wordle-style games — see the full Wordle strategy guide — and every length referenced above has its own list on the words-by-length hub.