Plain definitions for the language of sports betting.
US format. A + or − number relative to a $100 bet.
Positives like +150 are the profit on a $100 bet. Negatives like −200 are the stake required to profit $100. The default juice on spreads and totals is −110 on each side.
Example. +150 means a $100 bet wins $150 profit. −200 means a $200 bet wins $100 profit.
Total return per $1 bet, including your stake back.
Standard in Europe, Australia, and Canada. Cleaner than American odds for EV and implied-probability math because the number is already a multiplier.
Example. Decimal 2.50 means a $1 bet returns $2.50 total — $1.50 profit plus your $1 back.
Profit-to-stake ratio, written as a fraction.
The traditional UK format, now mostly used for horse racing. Numerator is profit, denominator is stake.
Example. 3/2 means a $2 bet wins $3 profit — $5 total return.
The win probability suggested by an odds quote, as a percentage.
Calculated as 1 / decimal odds × 100. Always includes the sportsbook's vig — true (no-vig) probability is slightly different. See no-vig odds.
Example. Decimal 2.00 implies 50%. Decimal 4.00 implies 25%.
A bet on which team wins outright. No spread.
The most basic sports bet. Favorites pay less than even money; underdogs pay more.
Example. Steelers ML at −150 — risk $150 to win $100 if Pittsburgh wins.
A point handicap added to one team's score to level the bet.
The favorite "gives" points (e.g., −7) and must win by more than the spread. The underdog "gets" points (+7) and can lose by less or win outright. Standard juice is −110 on each side.
Example. Chiefs −7 vs Broncos +7: KC must win by 8 or more for the −7 side to cash.
A bet on whether the combined score will be over or under a number.
Independent of who wins. Priced at standard −110 juice on most major markets.
Example. Total 48.5: bet over (49+ combined points) or under (48 or fewer).
A single bet on multiple outcomes; all must hit to win.
Payout is the product of each leg's decimal odds. The vig compounds across legs, which is why parlays favor the house — and why sportsbooks promote them so aggressively.
Example. Three −110 (decimal 1.91) legs combine to ~6.97. A $100 parlay pays $697 if all three hit.
A parlay built from outcomes within a single game.
Pricing is murky because the legs are correlated (e.g., a team scoring a lot and its QB throwing for many yards aren't independent). Sportsbooks price extra margin to compensate, so SGPs typically carry worse value than separate-game parlays.
Example. Chiefs to win + Mahomes 250+ passing yards + game total over 47.5, combined into one bet.
A parlay where each leg's spread or total is adjusted in your favor in exchange for a worse price.
Common in NFL. A 6-point teaser shifts every leg's number by 6 in the direction you want, but each leg's payout drops accordingly. Sharps occasionally find +EV teasers around key numbers (3, 7).
Example. A 2-team 6-point teaser turns Chiefs −7 into Chiefs −1, and over 48 into over 42.
A bet on a specific in-game event or player performance, not the final result.
Examples: first team to score, player rushing yards, total touchdowns. Player props have looser pricing than main lines, which is why sharps focus there.
Example. "Travis Kelce over 65.5 receiving yards" at −115.
A bet on an outcome that won't resolve until later in the season or beyond.
Long holding period and high vig — sportsbooks price futures with double-digit margins. Tying up bankroll for months on a negative-EV bet is rarely worth it.
Example. Chiefs to win the Super Bowl at +500, decided months from now.
Wagering on a game that's already in progress.
Lines update in seconds. Vig is typically higher than pre-game, and the speed of execution favors the sportsbook over the bettor. Useful mostly for hedging existing pre-game positions.
Example. Betting Eagles +2.5 at halftime after they've fallen behind by a touchdown.
The average profit per bet if the bet were repeated thousands of times.
Formula: EV = (P_win × profit) − (P_loss × stake). Positive EV means the bet is profitable in the long run, even when any single bet can lose. Every +EV decision is one a sharp will repeat.
Example. A $100 bet at +150 with a true 45% win probability has EV of (0.45 × $150) − (0.55 × $100) = +$12.50 per bet.
A formula for the optimal bet size relative to bankroll, given your edge.
f* = (b·p − q) / b, where b = decimal odds − 1, p = your true win probability, q = 1 − p. Full Kelly maximizes long-run growth but is brutally volatile; most sharps use half or quarter Kelly to dampen variance from estimate error.
Example. A 5% edge on a +100 bet → Kelly suggests 5% of bankroll. On $1,000, that's $50 full Kelly or $25 half Kelly.
Betting all outcomes of an event across different sportsbooks for a guaranteed profit.
Exists when the sum of implied probabilities across the books is below 100%. Returns are typically thin (1–5%) and the operational cost — funding multiple accounts, executing fast, surviving account-limiting — is real.
Example. Book A: Eagles +130. Book B: Patriots +120. Split $100 across both to guarantee a small profit either way.
A bet on the opposite outcome of a position you already have, to lock in profit or limit loss.
Common with parlays close to cashing — bet against your last leg to guarantee profit regardless of the result. Hedging always reduces your maximum upside in exchange for certainty.
Example. Your 4-leg parlay needs only the Chiefs to win for a $1,000 payout. Betting the opposing moneyline at the right size locks in profit either way.
A scenario where two opposing bets at different lines can both win on the same outcome.
Sportsbooks set the same game at slightly different lines. You bet one side at one number and the opposite side at another — if the result lands inside the overlap (the "middle"), both bets cash.
Example. Chiefs −3 at one book and Broncos +5 at another. If Chiefs win by exactly 4, both bets win.
The difference between the odds you bet at and the odds at game time.
Sharp bettors track CLV because closing lines are the most efficient market prices available. Consistently beating the closing line is one of the best leading indicators of long-term +EV betting.
Example. You bet Eagles +6 at −110. The line closes at Eagles +4. You beat the close by 2 points — a positive CLV signal.
The implied probability of an outcome with the sportsbook's vig stripped out.
Used to estimate "true" probability for EV calculations. Common method: divide each side's implied probability by the sum of all sides' implied probabilities.
Example. A −110/−110 market has implied probabilities of 52.38% each (sum 104.76%). No-vig: 52.38 / 104.76 = 50% each.
The total money set aside specifically for betting.
Should be money you can afford to lose entirely. Kelly sizing, unit sizing, and any responsible discipline all assume your bankroll is separate from rent and groceries.
Example. A $2,000 bankroll. If your unit is 1% of bankroll, each standard bet is $20.
The sportsbook's built-in commission on every bet.
On a standard −110/−110 spread, the vig is about 4.55% — the bookmaker's cut whether you win or lose. Lower-juice books (e.g., −105) noticeably improve long-run EV.
Example. At standard juice you need to win 52.38% of −110 bets just to break even.
The sportsbook's expected profit on a market, as a percentage of total handle.
Equal to the implied-probability sum minus 100%. The book's long-run edge — distinct from vig, which is per-bet juice.
Example. A two-way market at −110/−110 has a hold of about 4.76%.
A bet that ends in a tie — neither win nor loss. Stake is refunded.
Happens when the result lands exactly on a whole-number spread or total. Sportsbooks avoid pushes by using half-points (e.g., −3.5 instead of −3) on most lines.
Example. You bet Chiefs −7. They win by exactly 7. Push — stake refunded.
A market the sportsbook has temporarily removed from betting.
Usually pulled because of late-breaking news (injury, weather) or because the line is moving too fast to maintain. Reopens once books have updated the price.
Example. A starting QB is ruled out 90 minutes pre-game; the market goes OTB while books re-price.
The maximum bet a sportsbook will accept on a given market.
Higher on main lines (NFL spreads), much lower on props and obscure markets. Books also apply per-account limits — sharp bettors and arb players get limited the most.
Example. A typical NFL side might have a $5,000 limit; a Tuesday-night MAC game total might have a $200 limit.
A rapid, simultaneous line move across multiple sportsbooks driven by sharp money.
When sharps hit a number heavily at one book, others follow within seconds to avoid being middled. Recognizable by speed and uniformity.
Example. A −3.5 line at every major book moves to −5 within 90 seconds of a respected syndicate placing a bet.
Bets placed by professional or otherwise highly skilled bettors.
Distinguished from public money both by size and by track record. Sportsbooks monitor sharp action because it carries information — the line moves to reflect it.
Example. A line moves toward a side getting 30% of bets but 70% of the money — sharp action.
A casual or unsophisticated bettor.
Industry slang. Squares typically bet favorites, overs, and parlays on the visible big games. Sportsbooks lean their pricing slightly to capture square money.
Example. "The line moved up because of square money on the favorite all week."
The aggregate behavior of casual (square) bettors on a market.
Public-bet percentages are tracked publicly. Fading the public — betting against where most casual money goes — is a common but not automatically +EV sharp angle.
Example. "82% of bets on the over" is a public-side reading.
A standardized bet size used to compare results independent of bankroll.
Usually 1–2% of bankroll. Quoting performance in units lets bettors compare records without revealing dollar amounts.
Example. "Up 12 units this season." If your unit is $50, that's $600 in profit.
The side expected to win, priced at negative American odds (or under 2.00 decimal).
Slang: "fave," "chalk." Heavy favorites carry high implied probability and a small payout per dollar wagered.
Example. Chiefs ML at −350 — they're the favorite to win.
The side expected to lose, priced at positive American odds (or above 2.00 decimal).
Slang: "dog." Bigger payout per dollar in exchange for a lower implied win rate.
Example. Broncos ML at +275 — they're the underdog.
A spread bet wins because the team beats the point spread.
A favorite covers by winning by more than the spread. An underdog covers by losing by less than the spread — or winning outright.
Example. Chiefs −7 cover: they win by 8 or more. Broncos +7 cover: they lose by 6 or less, or win.
A bet that loses in particularly unlucky fashion at the last moment.
Common scenarios: a backdoor cover by garbage-time touchdown, a last-second free throw ruining a total, a deflected pick-six. Universally despised; story-trade currency in any sports bar.
Example. You're +7 with 8 seconds left and a 6-point lead. The losing team kicks a meaningless field goal and you lose by half a point.
Money currently wagered on a market, or the act of having a bet placed.
"Have action on" = have a bet on. Also used by sportsbooks to describe the total volume of wagers on a market.
Example. "I have action on the late game" = I've bet on the late game.