The letter O in Scrabble
8 in the bag · 1 point · 8% of all tiles
Drawing 7 tiles from a full bag, the letter O shows up about one rack in 2 — the 4th likeliest tile to see of 27.
How many you can expect
Most racks hold none at all — 54.7% of them, and 9.64% hold two or more. On average a rack carries 0.56 of them.
Exact chance of holding each number of O tiles in an opening rack of 7.
Is it a bingo tile?
A rack picked at random can play all seven tiles 12.6% of the time. A rack holding at least one O manages 11.7% — only 0.93× the baseline, which makes it the 12th best bingo tile of 27. Measured against ENABLE, which is public domain. The official lists are both bigger, so both would give a higher number — a little higher for NWL, appreciably so for Collins.
The reason is countable rather than folklore. 36% of the 19,424 seven-letter words in ENABLE use an O somewhere in them. A tile that appears in more words is a tile more racks can build around, and that is the whole of the effect above.
One caveat worth stating: this is a fact about whole opening racks holding an O, averaged over every set of six tiles it could arrive with. It is not a leave value. Whether to keep this tile mid-game depends on the six tiles beside it and on what is left in the bag, and a tile that is good on average can still be the wrong keep.
What it’s worth carrying
O is worth 1 point, which puts it 11th lowest-scoring tile of 27 — tied with 9 others at the same face value. Face value tracks rarity by design, but not as hard as people assume: the whole set is worth 187 points, and the five one-of-a-kind tiles (J, K, Q, X, Z) carry only 22% of that between them. The ten one-point letters carry 36% — more than the whole high-value end, because there are so many of them. It is also one of the five vowels, which is the other reason it is common.