Ask Bookbreaker: real questions, real answers
Ask is the app’s plain-English page. Type a question about a price, a parlay or a bet size and it answers from the engine’s own arithmetic, with the table it used. These are the answers a fresh install gives, computed by release 0.1.36 when this page was built.
“Fair odds on -150 / +130”
Take the book's margin out of both sides of a market, to see each side's real chance.
Fair chances with the book's margin taken out: -150 is 58.2% (fair -139), +130 is 41.8% (fair +139). The book's margin is 3.36%.
Fair odds
| Price | Fair chance | Fair price |
|---|---|---|
| -150 | 58.2% | -139 |
| +130 | 41.8% | +139 |
“What does a -110 -110 +150 parlay pay?”
What a parlay pays against what it should, before you place it.
A 3-leg parlay pays $811.16 on $100 where $947.62 would be fair: its hold is 13.0%, and its expected profit on $100 is -$13.03. Only each leg's own price was given, so each leg is taken to carry the margin of a standard -110 / -110 market (4.55%), removed in proportion to its price. With both sides of a leg's market, Fair odds gives its real fair price. Legs in different games are close enough to independent that multiplying the probabilities is the right sum.
Parlay
| Legs | Pays $100 → | Should pay | Margin | Expected on $100 |
|---|---|---|---|---|
| 3 | $811.16 | $947.62 | 13.0% | -$13.03 |
“How much should I bet at +150 if I think it wins 45% of the time?”
A bet size from your own estimate, at a fraction of the Kelly stake.
Full Kelly says 8.3% of the bankroll. At 25% of that on a $1,000 bankroll, the stake is $20.83 (2.08%); tell me your bankroll for your own figure. It assumes your win chance is right.
Bet size
| Stake | Share of bankroll | Full Kelly |
|---|---|---|
| $20.83 | 2.08% | 8.33% |
“If I have ten $1 bets, what are the best 10 parlays to make $200?”
The question people really ask, answered with the chances rather than a pitch.
There is no recent read of live sportsbook odds (it needs an Odds API key), so every leg is a typical -110 bet whose other side is also -110: no edge by construction. With no edge, no plan reaches $200 from $10 more than 5.0% of the time ($10 divided by $200), and the book's margin takes some of that. Bold play (one big bet, then again with what is left) reaches it 3.9% of the time; for a bettor without an edge that is the plan the mathematics of gambling (Dubins and Savage) favours. All $10 on one parlay reaches it 3.1% of the time. Your 10 parlays of $1 each pay about $337 if they hit. At least one hits 1.9% of the time, and because each pays the target on its own, that is also the chance of reaching it. Splitting lowers the chance: each of the smaller parlays needs more legs to pay the target, and every leg pays the book's margin again. A round robin reaches the target 0.00% of the time but gets something back 81.2% of the time: it buys a smaller win more often, not the target. On average each $1 parlay is worth $0.66 (a loss of the rest to the book), and the whole plan returns $6.58 on $10. This describes the odds of the prices shown. It does not find a bet that beats the book, and nothing here places a bet. 21+. Gambling problem? Call or text 1-800-MY-RESET (1-800-697-3738).
The 10 parlays ($1 each)
| # | Legs | Price | Pays if it hits | Chance |
|---|---|---|---|---|
| 1 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 2 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 3 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 4 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 5 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 6 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 7 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 8 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 9 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
| 10 | 9 × a typical -110 bet | +33585 | $336.85 | 0.195% |
Ways to stake $10 toward $200
| Plan | Reaches the target | Gets something back | Average return |
|---|---|---|---|
| bold play | 3.89% | 3.9% | $7.78 |
| one parlay | 3.12% | 3.1% | $7.92 |
| 10 parlays | 1.94% | 1.9% | $6.58 |
| round robin, pairs of 5 | 0.00% | 81.2% | $9.11 |
How Ask works
Without an AI, Ask recognises the shape of a question (fair odds, a parlay, a bet size, a plan for a target, the best bets in your last read of odds, your own record) and runs the engine on it. Every number in the answer comes from that run. With your own Anthropic key it can take any question, and it still answers from the engine’s numbers rather than making figures up; with a local model through Ollama nothing leaves your Mac.
It describes the odds of the prices it is given. It does not find a bet that beats the book unless the prices show one, and it never places a bet. 21+. Gambling problem? Call or text 1-800-MY-RESET (1-800-697-3738).
What leaves your Mac when you use Ask → · Every calculator, worked on real prices →