Betting basics

How odds, spreads, totals and parlays work, with worked examples.

Sports betting has its own vocabulary, and the numbers can look cryptic at first. This guide explains the three bets you'll find on every game, how to read the prices, and how parlays are calculated. All the examples use credits, the way Play Money Sportsbook does.

Reading American odds

Every bet has a price, written as a number with a plus or minus sign. The sign tells you which way to read it.

A minus number is what you stake to win 100. At -110, a 110-credit bet wins 100. You get back 210 in total: your 110 stake plus 100 in winnings.
A plus number is what you win on a 100 stake. At +150, a 100-credit bet wins 150. You get back 250 in total.

You don't have to bet in hundreds. The price is a ratio, so at -110 a 55-credit bet wins 50, and at +150 a 20-credit bet wins 30.

Price	Stake	Winnings	Total back
-200	100	50	150
-110	100	91	191
+100	100	100	200
+150	100	150	250
+300	100	300	400

The bigger the minus number, the heavier the favorite and the less you win. The bigger the plus number, the bigger the underdog and the more you win.

The moneyline: who wins

A moneyline bet is the simplest one: pick the team that wins the game. The score doesn't matter, only the result.

Say the home team is -180 and the road team is +150. The home team is the favorite: you'd stake 180 to win 100. The road team is the underdog: a 100 stake wins 150 if they pull off the upset. If an NFL game ends in a tie, moneyline bets are a push and stakes are returned.

The point spread: by how much

The spread evens out a mismatch by giving the underdog a head start. The favorite has a minus number and the underdog has the matching plus number.

Say the home team is -3.5 and the road team is +3.5.

A bet on the home team at -3.5 wins if they win by 4 or more.
A bet on the road team at +3.5 wins if they win the game, or lose by 3 or fewer.

When a team beats its spread, it has "covered". Spread bets are usually priced near -110 on both sides, because the head start is meant to make the two outcomes about equally likely.

Half points exist so there's always a winner. When the spread is a whole number, such as -7, and the favorite wins by exactly 7, the bet is a push and stakes are returned.

The total: how many points

A total, also called an over/under, ignores who wins. You're betting on whether both teams' combined score finishes over or under a number.

If the total is 47.5 and the game ends 27 to 24, the combined score is 51, so the over wins. If it ends 20 to 17, the combined score is 37 and the under wins. Overtime points count.

Parlays: all or nothing

A parlay combines two or more picks into one ticket. Every pick, called a leg, has to win. If one loses, the whole ticket loses. In exchange, the payout multiplies with each leg.

Here's how the maths works for three legs at -110 each. A -110 bet returns about 1.909 credits for every credit staked. Multiply that for each leg:

1.909 × 1.909 × 1.909 = 6.958

So a 500-credit parlay returns 3,479 credits if all three win, a price of about +596. Three separate 500-credit bets at -110 would only win 455 each.

The catch is that the chance of winning shrinks just as fast. If each leg is a coin flip, one leg wins half the time, two legs win a quarter of the time, and three legs win one time in eight. Long parlays pay a lot because they rarely come in.

Why -110 and not +100

If a spread bet is a 50-50 proposition, a fair price would be +100: stake 100 to win 100. Sportsbooks charge -110 instead. The extra 10 is the book's margin, known as the "vig" or "juice". It means you need to win about 52.4% of your -110 bets just to break even, which is why beating a sportsbook over time is hard.

Glossary

Bankroll: The total you have available to bet. Here, your credit balance.
Chalk: The favorite. "Betting the chalk" means backing favorites.
Cover: To beat the point spread.
Favorite: The team expected to win, shown with a minus number.
Hook: The half point in a number such as 3.5, which rules out a push.
Juice or vig: The sportsbook's built-in margin on a bet.
Leg: One pick within a parlay.
Line: The current spread, total or price on a game. Lines move as kickoff approaches.
Push: A tie between you and the book. Your stake is returned.
Underdog: The team expected to lose, shown with a plus number.

A word on the real thing

Everything above works the same way at a real sportsbook, except the losses are real too. Play Money Sportsbook exists so you can enjoy the game without that. If you or someone you know has a gambling problem, call 1-800-GAMBLER.