American odds, implied probability, the vig, and why the price you see isn't the true probability. A ground-up explanation.
American odds are displayed as positive or negative numbers. They answer one question: how much do you win or risk relative to $100?
A line of -100 (sometimes called “even money” or “pick ’em”) means you risk $100 to win $100. This is the dividing line between favorite and underdog.
Every odds price encodes an implied probability. This is the win percentage the odds suggest. Converting is straightforward:
These implied probabilities include the vig, so they’re slightly higher than the “true” probability. When you add both sides of a two-way market, they’ll sum to more than 100%. The overshoot is the vig.
The vig is the sportsbook’s commission. It’s built into every price and guarantees the book profit regardless of the outcome. The most common example: both sides of a spread priced at -110.
This is why 52.4% is the breakeven win rate at standard -110 juice. You need to win 52.4% of your bets just to avoid losing money. At -105 juice (reduced vig), breakeven drops to 51.2%. At -120 (inflated vig), breakeven rises to 54.5%.
Some sportsbooks offer reduced juice (-105) to attract sharp bettors. Over thousands of bets, the difference between -110 and -105 juice is enormous. A bettor winning 55% of their bets at -110 earns 4.5 cents per dollar wagered. At -105, the same 55% earns 7.1 cents. That’s a 58% increase in profit for the same edge.
Reference table showing common NFL odds, their implied probability (with vig), true probability (vig removed), and payout per $100 risked.
| ODDS | IMPLIED PROB | PROFIT / $100 | TOTAL RETURN |
|---|---|---|---|
| -500 | 83.3% | $20 | $120 |
| -300 | 75.0% | $33 | $133 |
| -200 | 66.7% | $50 | $150 |
| -150 | 60.0% | $67 | $167 |
| -130 | 56.5% | $77 | $177 |
| -110 | 52.4% | $91 | $191 |
| -105 | 51.2% | $95 | $195 |
| +100 | 50.0% | $100 | $200 |
| +110 | 47.6% | $110 | $210 |
| +150 | 40.0% | $150 | $250 |
| +200 | 33.3% | $200 | $300 |
| +300 | 25.0% | $300 | $400 |
| +500 | 16.7% | $500 | $600 |
Implied probability includes the vig. To get the true (no-vig) probability, normalize both sides of a two-way market to sum to 100%.
Three main bet types dominate NFL wagering. Each asks a different question about the game:
Most NFL bettors focus on the spread because it levels the playing field. Moneyline bets on heavy favorites require risking a lot to win a little (-300 means risking $300 to win $100). Underdogs on the moneyline offer attractive payouts but win less often. Totals require a completely different analysis from sides. Our point spread guide covers key numbers, crossing thresholds, and how to read a spread line. For evaluating spread-betting performance, see what ATS means.
NoPunt tracks game total predictions separately from spread picks, with a dedicated model for over/under analysis.
Odds aren’t static. They shift continuously from the time they’re posted until kickoff, driven by several forces:
The closing line (the price at kickoff) is the most efficient number. Research consistently shows that closing lines are the best predictor of game outcomes. Beating the closing line (getting a better price early) is called closing line value (CLV), and it’s the single best predictor of long-term betting profitability.
No-vig odds strip the sportsbook’s commission out of the price, revealing the “true” probability the market assigns to each outcome.
No-vig odds matter because they let you compare your own model’s probability to the market’s true assessment. If your model says KC has a 65% chance but the no-vig market says 58%, you have a 7% edge. If your model says 59%, you might not have a meaningful edge at all once you factor in the vig you’ll pay.
NoPunt’s prediction model generates its own win probability from play-by-play data, then converts that probability to a fair line. The gap between NoPunt’s fair line and the market’s closing line determines the confidence tier.
The CLV tracker measures closing line value on every pick: did the market move toward our number after we published? Positive CLV means the market agreed with us. Negative CLV means we were on the wrong side of the move.
NoPunt snapshots prices from DraftKings, FanDuel, BetMGM, and Caesars every two hours from Wednesday through Monday during the season. This data feeds the line history table on each game’s matchup page, so you can see exactly when and how the market moved.
NoPunt publishes every pick with its odds, tracks CLV on every game, and never deletes a loss.