Betting Odds Explained

Odds tell you two things: how likely the market thinks an event is, and how much you get paid if you're right. The problem is that the betting world uses three different formats to express the same idea, and none of them were designed with clarity in mind. Here's how each one works, translated into what a single dollar returns.

American odds use a plus or minus sign. A positive number like +300 means a $1 bet returns $3 in profit (plus your dollar back, for $4 total). A negative number like -150 means you'd need to bet $1.50 to win $1 in profit. The bigger the plus number, the less likely the market thinks it'll happen. The bigger the minus number, the more likely. American odds are standard in US sportsbooks and are what most people encounter first.

Decimal odds are the simplest format. The number is your total return per dollar bet, including your stake. Decimal odds of 3.00 mean $1 returns $3 total ($2 profit plus your original $1). Decimal odds of 1.50 mean $1 returns $1.50 total ($0.50 profit). To convert your implied probability, divide 1 by the decimal odds: 1 ÷ 3.00 = 33.3% implied probability. Decimal odds are standard in Europe, Australia, and Canada.

Fractional odds show your profit relative to your stake. Odds of 5/1 (spoken as 'five-to-one') mean you win $5 for every $1 you bet. Odds of 1/4 ('one-to-four' or 'four-to-one on') mean you win $0.25 for every $1. Fractional odds are traditional in UK horse racing and older British sportsbooks. They're falling out of favor because decimal odds are easier to calculate, but they persist because tradition is powerful and horse racing is stubborn.

Here's the same bet in all three formats, at various probabilities. At roughly 50% implied probability: American -110, decimal 1.91, fractional 10/11. At roughly 33%: American +200, decimal 3.00, fractional 2/1. At roughly 10%: American +900, decimal 10.00, fractional 9/1. At roughly 1%: American +10000, decimal 101.00, fractional 100/1. The Dollar Bets board always shows the $1 payout directly, so you don't need to convert — but knowing how helps when you're reading odds elsewhere.

Odds reflect the market's implied probability, but they're not pure probability — they include the bookmaker's margin (called the vig, juice, or overround). A fair coin flip should be +100 (2.00 decimal, 1/1 fractional), but a sportsbook might price it at -110 on both sides, guaranteeing themselves a profit regardless of the outcome. Prediction markets work differently: the price is set by supply and demand between traders, not by a house setting the line.

Every bet on the Dollar Bets board is expressed as what $1 could return. We strip away the format confusion entirely. If a contract is priced at 10 cents, your $1 payout is $10. If it's priced at 2 cents, your $1 payout is $50. The color-coded tier labels — from green (respectable) to purple (generational) — give you an instant read on how unlikely the market thinks the outcome is, without needing to parse American, decimal, or fractional anything.