Betting Odds Calculator

Sportsbooks set spreads to get equal action on both sides. The -110 on each side creates a 4.55% margin (vig) for the house. If both sides are bet equally, the book profits regardless of outcome.

At -110 odds, you need to win 52.38% of your bets to break even. To be profitable long-term, you need to consistently win more than 52.4%. Most professional bettors aim for 54-58% win rates.

For negative American odds: (100 / |odds|) + 1
For positive American odds: (odds / 100) + 1

Example: -110 = (100/110) + 1 = 1.909
Example: +150 = (150/100) + 1 = 2.50

Implied probability is the likelihood of an outcome based on the betting odds. It tells you what percentage of the time an event would need to occur for the bet to break even. -110 implies a 52.38% chance.

Vig (vigorish) or juice is the commission sportsbooks charge on bets. It's built into the odds. When both sides are -110, the vig is 4.55%. Lower vig means better value — some books offer -105 on spreads (2.44% vig).

Convert each leg to decimal odds, multiply them together, then convert back to American if needed.

Example: -110 and +150 parlay
1.909 × 2.50 = 4.773 decimal = +377 American

Mathematically, no. The vig compounds with each leg, making parlays high-risk bets with negative expected value. A 2-leg parlay has ~8.8% vig vs 4.55% for single bets. However, they can be fun with small stakes.

No-vig odds remove the sportsbook's margin, showing the "true" implied probability. If a market is -110/-110, the no-vig fair odds are +100/+100 (50% each). This helps identify value.

Each book sets its own lines based on its risk models and betting action. This creates opportunities to "shop" for the best lines. Even a half-point difference or -105 vs -110 adds up over thousands of bets.

+EV means positive expected value. A bet is +EV when your estimated probability of winning exceeds the implied probability in the odds. Professional bettors focus exclusively on finding +EV opportunities.

Compare your estimated probability to the implied probability. If you think a team has a 58% chance but odds imply 52%, that's value. Build models, track line movement, and shop multiple books.

Moneyline: Bet on who wins outright. Favorite has negative odds, underdog has positive.

Spread: Bet on margin of victory. Favorite must win by more than the spread (-7), underdog can lose by less than the spread (+7) or win outright.

A push occurs when the result lands exactly on the spread or total (e.g., team wins by exactly 7 when spread is -7). Your bet is refunded. Half-point spreads (-7.5) eliminate pushes.

Buying points means paying worse odds to get a more favorable spread. Moving from -7 to -6.5 might cost you -120 instead of -110. It's usually not worth it mathematically except around key numbers (3, 7 in NFL).

Key numbers are the most common margins of victory. In NFL: 3 (field goal), 7 (touchdown), 10, 6, 14. Games land on 3 about 15% of the time. Getting +3 instead of +2.5 is significant.

Line movement is when odds change from their opening number. Lines move due to betting action, injury news, or sharp money. Tracking movement helps identify where professional bettors are betting.

Sharp money comes from professional bettors with winning track records — books respect their action and move lines accordingly. Square money comes from recreational bettors and typically favors favorites and overs.

Most bankroll management strategies suggest 1-5% of your total bankroll per bet. Conservative bettors stick to 1-2%. This protects against variance and ensures you can survive losing streaks.

CLV measures whether you got better odds than the final line before the game. Consistently beating the closing line is the best predictor of long-term profitability — it means you're identifying value before the market corrects.

It depends. Bet early if you expect the line to move against you (sharps often bet Sunday/Monday for NFL). Wait if you expect favorable movement or need injury news. Track line movements to develop intuition.

A teaser is a parlay where you adjust spreads/totals in your favor by 6-7 points per leg in exchange for reduced odds. A 6-point 2-team NFL teaser at -110 can be +EV when crossing key numbers (moving through 3 and 7).

Very accurate. Closing lines are considered the most efficient predictor of game outcomes because they incorporate all available information and sharp action. However, they're not perfect — that's where value betting comes in.