Odds Basics: Moneyline, Run Line, and Totals
First thing – odds are a price tag on a prediction. Moneyline? It’s the simplest: a plus sign means the underdog, a minus sign the favorite. +150 tells you a $100 bet could net $150. -120 means you must risk $120 to win $100. No fluff.
Run line throws a spread into the mix. Usually set at -1.5 for the favorite, +1.5 for the underdog. It’s not about who wins, it’s about the margin. If the Yankees are -1.5 at -110, they have to win by two runs or more, and you risk $110 to earn $100.
Totals, aka over/under, predict combined runs. 8.5 runs at +105 means you win $105 on a $100 stake if the game tops 9 runs. Drop the decimal, hit the line.
Decoding the Numbers: Implied Probability
Convert odds to a win probability. For minus odds, divide the absolute value by (value + 100). -150 → 150/(150+100)=0.60 or 60%. For plus odds, 100/(odds + 100). +130 → 100/(130+100)=0.43 or 43%. This is your baseline.
Compare that baseline to your own assessment. If you think the Dodgers have a 70% chance to win, but the odds imply 55%, you’ve spotted value. That’s the sweet spot where the moneyline becomes a profit engine.
Adjusting for Run Line and Totals
The run line skews the probability. A -1.5 line at -110 translates roughly to a 52.4% implied chance. If your model says the game is a 60% shooter, you’re looking at a positive edge. Same with totals: use a Poisson distribution or simple averages to gauge expected runs, then match that against the offered line.
Remember, the bookmaker builds a margin – the vigorish. It’s baked in. Strip it out. For a pair of odds like -110 / -110, the true probability totals 100% + vigorish. To find the fair odds, calculate 1/( (1/0.476)+(1/0.476) ) ≈ 0.476 each, then invert. That reveals the hidden cost of the spread.
Live Betting: The Odds Evolution
Live odds swing like a pendulum. A home run early can shift a run line from -1.5 to -2.5 in seconds. Keep a radar on momentum, bullpen fatigue, and weather. The longer the game runs, the more data you have – and the more the odds reflect reality, not just hype.
Use the same conversion trick on live odds. If the Royals are +160 at the 7th inning, that’s a 38.5% implied chance. If your in‑game model says they’ve got a 55% chance, you’ve uncovered a live arbitrage.
Bankroll Management: The Real Edge
Even the sharpest odds are useless without discipline. Kelly Criterion? Yes. Bet fraction = (bp – q)/b, where b = odds decimal, p = your probability, q = 1 – p. If you think a -120 line has a 60% edge, the Kelly fraction tells you to risk ~4% of your bankroll.
Don’t chase. Odds can flip in a heartbeat. Stick to the numbers, not the gut.
Putting It All Together
Start by converting every odd to its implied probability. Slice away the vigorish. Stack your own model on top. Spot the mismatches. Apply Kelly or a flat‑bet rule. When the line moves, recalc. That’s the machine.
Here’s the deal: grab the odds, do the math, trust the edge, and place that bet.
