What is a prop bet?

The short answer

"Prop" is short for proposition. A prop bet is a wager on a specific event or number within a game or a season. It does not depend on the final score or on who wins. Common examples are how many yards a quarterback throws for, whether a player scores a touchdown, or how many points are scored in the first quarter.

Props use the same odds language as any other bet. They are written as American odds, and the same arithmetic gives the profit, the break-even rate and the sportsbook's margin. What is different is the market: there are far more of them for each game, and the rules for when a prop counts are more specific than for a moneyline.

The main kinds of prop

Player props

A player prop is about one athlete's performance. The usual form is an over/under on a stat, such as passing yards, receptions, rebounds or strikeouts. The sportsbook sets a number, and you bet that the player finishes over it or under it.

Game props

A game prop is about the game itself rather than a single player. Examples include which team scores first, whether the game goes to overtime, or the total for one half or one quarter.

Yes or no props

Some props are a plain yes or no. Will a particular player score a touchdown? Will there be a safety? Each side has its own price, and the yes side usually pays more when the event is unlikely.

Futures-style props

A few props settle at the end of a season, such as a player winning an award or a team reaching a win total. The money is tied up for months, which is worth keeping in mind before you place one.

How an over/under prop is priced

Take a player prop set at 64.5 receiving yards. The over is priced at -115 and the under at -105. A $100 stake on the over wins $86.96 in profit if the player gets 65 yards or more. A $100 stake on the under wins $95.24 if the player gets 64 or fewer. The half point means a bet cannot tie, because yardage is a whole number.

The two prices imply chances of 53.5% and 51.2%. Together they add up to 104.7%, which is more than 100%. The extra 4.71% is the sportsbook's margin. Remove it and the fair chances are about 51.1% for the over and 48.9% for the under, which correspond to fair prices of about -104 and +104. A market at -110 on both sides carries 4.76%. The odds calculator does this for any pair of prices.

Look at the margin of the prop, not only of the main game line. Margins on props can differ from the margin on a moneyline, so a prop is not automatically a better or a worse deal. The only way to know is to compute it.

A yes or no prop from slip to result

Say a player to score a touchdown is priced at +250. A $20 stake wins $50.00 in profit, and the winning bet returns $70.00 in total with your stake. The price implies a 28.6% chance, so the bet has to win more than that share of the time to come out even.

If the player scores, the bet wins, even if his team loses by three touchdowns. If he does not, the $20 is gone, even if his team wins easily. A prop is settled on its own event and nothing else.

Rules that decide whether a prop counts

The most common source of confusion with props is what happens when the player does not play. House rules differ by app and by market. A player prop may be voided, with your stake returned, or it may count as a loss, if the player does not take the field. Some markets count only regulation time and some include overtime. The app shows the rules for each market, and the house rules page explains how it settles postponed or shortened games. Read them before you bet, not after.

The source of the statistics matters too. The app's rules page says which data it uses to settle a prop, so look there before you bet.

What the regulators say

Regulators can narrow which props may be offered. New York is a clear public example: the Gaming Commission's sports wagering page says wagers based on an official statistic of the sport with no negative implication are generally acceptable. Our New York page quotes the wording and links to the source. Other states set their own limits, and a market available in one state may be missing in another. The state law table shows which states we have checked against official pages.

The same prop at two apps

Suppose two apps list the same prop at the same number, 64.5 receiving yards. The first prices the over at -115 and the under at -105. The second prices both sides at -110. The over needs to win 53.5% of the time at the first app and 52.4% at the second. The under is the other way round: it is cheaper at the first app. The margin is 4.71% at the first app and 4.76% at the second.

That is a small gap, and it shows why a single price tells you little. The better price depends on which side you want, so compare the side you intend to bet, not the whole market. Having an account at more than one app is what makes that comparison possible, and doing it takes a minute.

Why the half point matters

Props are often set at a half point, such as 64.5, so that a whole-number stat cannot land exactly on the line. If a prop is set at 65 and the player finishes with exactly 65, the bet is a push. Most apps return the stake on a push, and the app's rules say how it treats one. A half point removes that outcome, which is why it looks like a small detail and still changes the bet. At a whole number, a push takes some of the probability away from both sides, so the prices on the two sides are not directly comparable to prices at a half point.

What a run of props costs

Props are easy to stack, because each stake looks small. As an illustration, ten props a week at $20 each puts $200 at stake. If the true chances matched the margin-free chances at the -115 price, the average result on each bet would be a loss of about 4.5% of the stake, or about $8.99 a week across the ten. Real results swing far above and below that average from week to week, and it is only an average, but it is the price of playing. Keep a note of the total you stake, not just the size of each bet.

Props in a parlay

Props are a popular choice for parlay legs, and many apps let you combine several props from the same game. The arithmetic is the same as any parlay: the decimal prices multiply and every leg has to win. When legs come from the same game, the outcomes are often linked, because one player scoring more can mean the team scores more. Apps may price that link into the combined odds, so you cannot assume the single prices multiply the way they do for separate events. Read the article on what a parlay is and use the parlay calculator for tickets built from separate events.

Why a prop line moves

A prop number is not fixed. News such as an injury report, a change in the expected weather or a lineup change can shift the line or the price within minutes. The price you get is the price on the slip when you confirm, so an app may ask you to accept a changed number before it takes the bet. A prop line that moved after you looked is a reason to recompute the break-even rate, not a reason to hurry.

Common mistakes with props

• Judging a prop by how likely the player feels to do it, without comparing it to the break-even rate of the price.
• Ignoring what happens if the player does not play, and finding out after the game.
• Assuming props carry the same margin as the main game line.
• Betting many props at once because each stake is small, and losing track of the total.
• Assuming every prop on one app is available in your state or on another app.

A short checklist before you place one

• What exact event or stat does the prop settle on, and from which source?
• What happens to the bet if the player does not play or the game is shortened?
• What win rate does the price need, and is your estimate above it?
• Is the total you have set aside for the day still unchanged after this bet?

Words you will meet

• Prop: short for proposition, a bet on an event inside a game or season.
• Over/under: a bet that a stat finishes above or below a number set by the sportsbook.
• Void: a bet that is canceled and returns your stake.
• Line: the number a prop is set at, such as 64.5 yards.
• Margin: the amount by which the implied chances in a market add up to more than 100%.

Keeping it in proportion

Props make betting feel more personal, because the wager follows one player through a game. That can make it easier to bet more than you planned. Decide how much you can afford to lose before you start, keep stakes small, and treat any result as entertainment spending. When betting stops being fun, the responsible gambling page has tools and places to get help, and 1-800-GAMBLER answers at any time. To practice reading prices, try the odds quiz or the odds course.

Frequently asked questions