American sportsbooks default to moneyline odds — plus and minus numbers that confuse a lot of new bettors until the logic clicks. Once it does, spotting the vig baked into every line gets a lot easier.

Every number a sportsbook posts includes its cut. Understanding moneyline format, how it converts to implied probability, and how spreads and totals get priced separately is the difference between betting blind and knowing exactly what you're paying for.

Moneyline odds: the US default

Moneyline odds are written as a number with a plus or minus sign, always relative to a $100 baseline. A minus number shows how much you need to stake to win $100; a plus number shows how much you win on a $100 stake. At -110, you risk $110 to win $100. At +150, a $100 stake wins $150 profit.

The sign tells you favourite from underdog instantly. Minus numbers (-110, -200, -350) mark the favorite — you stake more to win less, because the book considers the outcome more likely. Plus numbers (+120, +150, +400) mark the underdog — smaller stake required for a bigger payout, reflecting lower perceived probability.

The vig (or juice)

The vig — short for vigorish, also called juice — is the sportsbook's built-in commission, most visible on a standard point spread bet priced at -110 on both sides. Bet either side of a coin-flip spread at -110 and the book profits regardless of outcome, because you're risking $110 to win $100 on a genuinely 50/50 proposition. That gap is the vig.

Convert -110 to implied probability and you get roughly 52.4% — meaning the book needs to be right slightly more than half the time on a true coin flip just to break even, with everything above that as profit. Shopping the same line across multiple sportsbooks and finding better pricing (-105 instead of -110, for instance) is one of the most direct ways to reduce how much vig you're paying over a season.

Converting moneyline to decimal and implied probability

For underdogs (plus odds): decimal = (moneyline ÷ 100) + 1. At +150, that's 1.5 + 1 = 2.5.

For favorites (minus odds): decimal = (100 ÷ absolute value of moneyline) + 1. At -200, that's 0.5 + 1 = 1.5.

Implied probability is 1 ÷ decimal odds × 100. At -200 (decimal 1.5), that's 1 ÷ 1.5 × 100 = 66.7%. The book is pricing that side as roughly a two-in-three shot.

Point spreads: pricing the margin, not just the winner

A point spread handicaps the favorite by a set number of points, and both sides are typically priced close to -110. If the spread is -6.5 on the favorite, they need to win by 7 or more for a spread bet to cash; the underdog at +6.5 covers by either winning outright or losing by 6 or fewer. The half-point exists specifically to eliminate ties ("pushes").

Spreads and moneylines price the same game differently on purpose. A heavy favorite might be -6.5 on the spread but -280 on the moneyline — the spread bet is a coin-flip-priced wager on margin of victory, while the moneyline is a straight bet on who wins, priced according to how lopsided the matchup actually is.

Totals (over/under)

A totals bet is a wager on the combined score of both teams, set by the book at a number designed to draw roughly equal action on both sides. Like spreads, totals are usually priced close to -110 each way, with the vig working identically to a point spread bet. Alternate totals — set higher or lower than the main number — carry different odds to compensate for the shifted probability.

A worked parlay example

Parlay payouts multiply the decimal odds of each leg together, which is why combining bets grows the potential payout quickly — and why the vig compounds with every added leg. Three independent legs at -110, +130 and -150, converted to decimal (1.909, 2.3, 1.667), multiply together to roughly 7.32. A $50 parlay at combined decimal 7.32 returns about $366 total, or roughly $316 profit.

Each leg's individual vig compounds across the full parlay. If each -110 leg individually carries close to a 4.5% house edge, a three-leg parlay combining similarly-priced legs can carry an aggregate house edge well above 10% by the time all three are multiplied together — a meaningfully worse proposition per dollar staked than any single leg bet, even though the headline payout number looks considerably more attractive.

Chalk, dogs and futures

"Chalk" refers to the favorite — the expected winner, the safer but lower-paying side of a bet. "Dog" (short for underdog) is the opposite: a team or player priced to lose more often than not, carrying plus-money odds as compensation for the lower implied probability. Betting "against the chalk" means backing the underdog specifically because you disagree with how heavily the market favors the favorite.

Futures are long-term bets placed well before an outcome is determined — a team to win a championship before the season starts, a player to win an MVP award, a division winner months in advance. Futures odds move continuously as the season unfolds; a preseason futures price locked in early can look very different from the same market's price by midseason, but your original odds are honored regardless of how the line has since moved.

Teasers

A teaser lets you adjust the point spread or total in your favor across multiple legs, in exchange for reduced payout odds compared to a standard parlay. A common NFL teaser moves each spread by 6 points — turning a -7 favorite into a more comfortable -1, for instance — applied uniformly across every leg in the teaser. Because you're buying better odds of each individual leg hitting, the payout is priced lower than an equivalent standard parlay would offer.

Teasers are typically restricted to spread and total bets, not moneylines, and most sportsbooks require a minimum number of legs (commonly two) to qualify. The math favors the bettor on any single leg but the combined payout reduction usually offsets that advantage across the whole teaser, similar in principle to how cash out offers trade certainty for reduced value.

Frequently asked questions

Why is almost everything priced at -110?

-110 on both sides of a two-way market is the traditional standard vig in US sports betting, roughly a 4.5% house edge on a genuine coin flip. Some books price more competitively (-105 or even pick'em lines) specifically to attract volume, so comparing sportsbooks on the same game is worth the extra minute.

What's the difference between the moneyline and the spread on the same game?

The moneyline is a bet purely on who wins; the spread is a bet on the margin, artificially balanced by the sportsbook to price close to a coin flip regardless of how lopsided the actual matchup looks. A team can cover the spread while losing outright, or win outright while failing to cover.

Why do odds move between the time a line opens and game time?

Sportsbooks adjust lines based on where money is being placed, aiming to balance liability on both sides. Heavy betting on one side typically shortens that side's price and lengthens the other.

What does "pick'em" mean?

A game so evenly matched the sportsbook sets no favorite on the moneyline — both sides carry roughly even odds, typically close to -110 or occasionally even money.

Is a plus-money underdog ever a smarter bet than the favorite?

Mathematically it depends entirely on whether the book's implied probability is accurate, not on the size of the number itself. A well-priced +150 underdog and an overpriced -140 favorite can both be poor value depending on the true probability of the outcome.

How is a parlay's payout calculated from individual moneylines?

Each leg's decimal odds are multiplied together, then converted back to a combined payout. This compounds the vig across every leg, which is why parlays carry a larger built-in house edge than single bets.

This guide is for educational purposes. Betting involves financial risk and no method of reading odds guarantees a profitable outcome. 21+ and physically present in a state where the operator is licensed. Gambling problem? Call 1-800-MY-RESET or 1-800-522-4700 (National Problem Gambling Helpline). Information correct as of October 2026.