Backgammon Doubling Cube Advisor
The doubling cube is where backgammon money is won and lost, and the underlying math is cleaner than most players think. Slide in your game-winning probability, add gammon rates if you know them, pick who owns the cube, and the advisor applies classical money-game cube theory: the dead-cube take point of 25%, how owning the recube pushes it down toward 20%, the doubling point where offering the cube starts to gain, the cash point where your opponent should pass, and the too-good threshold where you keep the cube and play on for the gammon. The verdict comes as a plain sentence — "Double, take" — alongside every threshold and a strip chart of the doubling window with your position marked, so you see not just the answer but how close the decision is.
Runs 100% in your browser — your puzzles never leave your device.
Read the full guide to this tool
Notes
- Formulas: with W and L the average points won per win and lost per loss (1 + gammon rate, ignoring backgammons), the dead-cube take point is (L − 0.5) / (W + L) and the live-cube take point is (L − 0.5) / (W + L + 0.5) — 25% and 20% in a gammonless race.
- Doubling window: doubling starts to gain at L / (W + L) (50% gammonless) and the opponent passes above the cash point; above (1 + L) / (W + L) you are too good — play on for the gammon instead of cashing 1 point.
- Money play only: match play take points shift with the score (Crawford, 2-away/2-away and friends are a different animal) and are out of scope here.
- Runs 100% in your browser — your words and puzzles never leave your device.
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