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How accurate are the NBA odds?

The closing prices of 1,975 finished games since Fri 24 Jan 2025, set against what happened: the chance the market gave, with the bookmakers' margin removed, next to how often it came in. A record of what the market did, not a tip.

The market's record

1,975 games, 2 bookmakers
  • Closing favourite won 69% 1,356 of 1,975 games
  • Market Brier score 0.394 0 is perfect; a coin flip scores 0.500
  • Average closing payout 95.7% 100% minus the bookmakers' margin
  • Games covered 1,975 Fri 24 Jan 2025 to Sun 14 Jun 2026

9 of the 1,984 games finished in that time are left out: no bookmaker had a closing price on every outcome.

Market chance against what happened

0-10% chance: happened 4.2% of 48 selections 10-20% chance: happened 12.5% of 399 selections 20-30% chance: happened 24.8% of 419 selections 30-40% chance: happened 37.7% of 541 selections 40-50% chance: happened 45.5% of 558 selections 50-60% chance: happened 54.3% of 578 selections 60-70% chance: happened 62.3% of 541 selections 70-80% chance: happened 75.2% of 420 selections 80-90% chance: happened 87.4% of 398 selections 90-100% chance: happened 95.8% of 48 selections 100% 0%
Market said 0%100%
Happened
Market chancePriceSelectionsMarket saidHappenedDiff
0-10% 10.00 or longer 48 8.5% 4.2% -4.3 pts
10-20% 5.00 to 10.00 399 15.0% 12.5% -2.5 pts
20-30% 3.33 to 5.00 419 25.0% 24.8% -0.2 pts
30-40% 2.50 to 3.33 541 35.2% 37.7% +2.5 pts
40-50% 2.00 to 2.50 558 44.8% 45.5% +0.7 pts
50-60% 1.67 to 2.00 578 55.0% 54.3% -0.7 pts
60-70% 1.43 to 1.67 541 64.8% 62.3% -2.5 pts
70-80% 1.25 to 1.43 420 75.0% 75.2% +0.2 pts
80-90% 1.11 to 1.25 398 85.0% 87.4% +2.4 pts
90-100% 1.11 or shorter 48 91.5% 95.8% +4.3 pts

Every priced outcome of every game is one selection. "Market said" is the bookmakers' average implied probability with the margin removed; "Happened" is how often that outcome came in. On the diagonal the market was right on average; above it, that kind of result happened more often than the prices said. Bands with fewer than 30 selections are left out.

Home, away

OutcomeMarket saidHappenedDiff
Home win 55.2% 55.2% 0.0 pts
Away win 44.8% 44.8% 0.0 pts

The market's average closing chance for each outcome over all 1,975 games against the share of games it won. "Home" is the first-named side.

Bookmaker accuracy

lower is better
BookmakerGamesBrier scorevs market averagePayout
Unibet 1,553 0.383 -0.002 95.4%
Bet365 1,072 0.396 +0.006 95.9%

Each bookmaker's own closing prices, margin removed, scored against the results of the games it priced; "vs market average" compares it with the bookmakers' average on the same games, so a negative figure means its prices were the closer. Bookmakers with fewer than 50 priced games are left out. Differences of a few thousandths are noise; a much higher score usually means the bookmaker's last price was captured well before the start, so it is the price in our archive being scored, not the trader.

Odds accuracy FAQ

How accurate are NBA odds?
Across 1,975 finished NBA games since 2025, the closing favourite won 69% of the time. The market's closing chance, with the bookmakers' margin removed, gave the home side 55.2% on average and home wins happened 55.2% of the time. The bands above show the same comparison price by price: a well-calibrated market has outcomes happening about as often as its prices say.
What is a Brier score?
The squared distance between the chances a bookmaker's prices gave and what happened, averaged over games: 0 would be perfect foresight, and on a three-way market a coin-flip price scores 0.667. The market average's closing prices score 0.394 in this league; the lowest single bookmaker is Unibet at 0.383. Differences of a few thousandths between bookmakers are noise, not skill.
Does a well-calibrated market mean the odds cannot be beaten?
Calibration says the market is right on average, not on every game. A band where outcomes happened more often than the prices said is where the closing market under-priced that kind of result over these seasons. The bookmaker's margin, about 4.3% here, still has to be cleared: the closing line value calculator shows what a price needs to beat.