Some letters carry a word. Others barely show up at all. Knowing which is which speeds up every unscramble, and it's the same math cryptographers use to crack a coded message.
English letters rank, most common to least, roughly as E T A O I N S H R D L C U M W F G Y P B V K J X Q Z. Herbert Zim's book Codes and Secret Writing gives cryptogram-solvers a near-identical order of their own, built for cracking coded messages rather than playing word games. That's worth noticing: the same math that breaks a cipher also tells you which letters are the safest first guess when you're staring at seven scrambled tiles.
There's a catch. The order above counts letters as they show up in ordinary writing, which means it's skewed by how often a handful of short words like "the" and "and" get reused. A word game doesn't care how often a word appears in a sentence. It cares how many different words exist at all.
Count distinct words instead of running text and the order shifts. S climbs into the top few letters, mostly on the strength of plural endings, even though it ranks lower by ordinary text frequency. That's the number that actually matters for word games, and it's exactly what the table below shows, counted from every word in this site's own dictionary.
Position matters too, and a single frequency number hides it. A study of Google's book-scan corpus found E is one of the rarest letters to START a word, roughly a quarter as common there as it is everywhere else, yet it's the single most common letter to END one. Lump "contains," "starts," and "ends" into one score and you lose exactly the distinction that would tell you that, which is why the table below keeps them separate. It's also why even the classic ETAOIN SHRDLU order isn't fixed: run the same analysis on a big enough sample of modern text and it comes out ETAOIN SRHLDCU instead, with L, R, and C each moving up a rank.
Scrabble and Words With Friends both price Z and Q at 10 points, as if the two tiles were equally hard to use. They aren't. Q is the rarer of the two by a wide margin: for every playable word holding a Q, roughly three hold a Z instead. If you're deciding which tile is actually worth clinging to, that's a more useful number than the points printed on it. See Scrabble & WWF Letter Value Strategy for the full tile-value breakdown.
A Carnegie Mellon study went further and simulated about ten million games to see which tiles actually help you win, not just how they're priced. Its verdict: S, Z, and X are the best tiles to hold onto, and Q is effectively a penalty tile, costing you roughly five points on average despite its ten-point face value. A blank is worth holding for the right moment too, worth about thirty points more played late than played early.
Some letters travel in pairs. TH, HE, AN, RE, ER, IN, ON, AT, ND, and ST are the most common two-letter combinations in English. Doubled letters follow their own pattern: LL, EE, SS, OO, and TT lead the list.
One pairing is worth calling out on its own. G shows up alongside I and N more than with any other letters, which is a big part of why -ING is worth checking for whenever you've got all three. See Recognizing Word Patterns & Common Endings for more.
Sources: Wikipedia's Letter Frequency article, Peter Norvig's Scrabble letter-score analysis and Mayzner Revisited letter-frequency study, "Letter distributions and word games" by Raymond Gallardo on BoardGameGeek, and Carnegie Mellon's "Lucky Letters" report on Andrew C. Thomas's Scrabble tile-value study.
| E | 1 | 70.0% | 4.1% | 9.8% |
|---|---|---|---|---|
| S | 1 | 60.1% | 11.0% | 37.9% |
| I | 1 | 59.0% | 4.0% | 0.5% |
| A | 1 | 54.3% | 6.1% | 1.7% |
| R | 1 | 52.5% | 5.9% | 5.5% |
| N | 1 | 48.7% | 2.5% | 4.4% |
| T | 1 | 48.2% | 5.1% | 4.9% |
| O | 1 | 45.9% | 3.4% | 0.6% |
| L | 1 | 39.7% | 2.9% | 3.2% |
| C | 3 | 31.9% | 9.4% | 2.2% |
| D | 2 | 27.2% | 5.9% | 9.2% |
| U | 1 | 26.9% | 2.9% | 0.1% |
| P | 3 | 23.5% | 8.4% | 0.6% |
| M | 3 | 23.0% | 5.6% | 1.5% |
| G | 2 | 22.1% | 3.2% | 7.6% |
| H | 4 | 19.4% | 3.6% | 1.1% |
| B | 3 | 15.4% | 5.4% | 0.1% |
| Y | 4 | 14.2% | 0.3% | 7.7% |
| F | 4 | 10.0% | 3.9% | 0.2% |
| V | 4 | 8.6% | 1.6% | 0.0% |
| K | 5 | 7.3% | 1.0% | 0.8% |
| W | 4 | 6.5% | 2.1% | 0.2% |
| Z | 10 | 4.1% | 0.3% | 0.0% |
| X | 8 | 2.7% | 0.1% | 0.2% |
| Q | 10 | 1.5% | 0.5% | 0.0% |
| J | 8 | 1.4% | 0.8% | 0.0% |
