Middles Calculator
Find middle bet opportunities where you bet both sides of a spread or total at different sportsbooks and potentially win both bets. Calculate the probability, expected value, and optimal stake split.
Sport:
Presets
Inputs
ABook A
Decimal: 1.909
VS
BBook B
Decimal: 1.909
$
Results
Expected Value+$5.91+EV Middle
Middle Window
3
3.5
Score margin3 pushes one side and wins the other
Window boundary on key number 3. A push on this number refunds one side while the other wins; that outcome is priced in the table below.
Chance the number lands in the window15.00%
NFL margin table (share of games decided by exactly that number, applied to the favourite's side)
Optimal Stake Split
Outcome Scenarios
ScenarioProfit / Loss
Margin exactly 3: Favorite pushes, Underdog wins 15.0%+$90.91
Side A wins only 85.0% for either miss -$9.09
Side B wins only -$9.09
Middle Window0.5 pts
Guaranteed Loss$9.09
ROI+2.95%
Breakeven Prob9.09%
Middling vs Straight Bet
Middle EV (both sides)+$5.91
Straight bet A only ($200.00)$9.09
Straight bet B only ($200.00)$9.09
Middling has higher EV than either straight bet alone.
Understanding Middle Bets
What is a Middle Bet?
A middle bet occurs when you find different spreads or totals at two sportsbooks, creating a "window" where the final result could land. If it does, both bets win. For example, if you bet Team A -3 at Book 1 and Team B +4.5 at Book 2, any final margin of 4 means both bets win. The key is finding line discrepancies between books.
Middles vs Arbitrage
In arbitrage, you guarantee a profit regardless of outcome. In a middle, you accept a small guaranteed loss if the middle doesn't hit, but win big if it does. Middles are higher variance but can have better long-term expected value because sportsbooks are less likely to limit players betting different sides at different spreads compared to obvious arb patterns.
Key Numbers and Middles
In NFL betting, certain margins occur far more frequently than others. The number 3 accounts for roughly 15% of final margins, and 7 accounts for about 10%. Middles that cross these key numbers are significantly more valuable. A middle spanning -3 to +4 in the NFL includes the key number 3, making it one of the most profitable middle opportunities available.
Risk Management for Middles
Optimal middle betting requires careful bankroll management. Since most middles will miss, you must size bets so the guaranteed loss is small relative to your bankroll (typically 1-2%). The key is ensuring the expected value is positive over hundreds of middles. Use the optimal stake split calculator to minimize your worst-case loss while preserving upside when the middle hits.
Keep what you worked out.
A free account saves your bankroll plans, sessions and the results you run here, on every device. No card, no upsell.
Next
Goes with this. Calculate payouts for spread and totals bets with key number analysis. NFL/NBA push probability tables and margin-of-victory distributions.
Open Spread/Totals Payout Calculator →Related tools
Spread/Totals Payout CalculatorCalculate payouts for spread and totals bets with key number analysis. NFL/NBA push probability tables and margin-of-victory distributions.Goes with thisArbitrage CalculatorFind guaranteed profit across 2+ sportsbooks. Input odds from different books and get the exact stake split for risk-free returns.Goes with thisHedge Bet CalculatorLock in profit on an open bet by calculating the optimal opposite-side stake. Essential when your parlay is 1 leg away from hitting.Goes with thisExpected Value CalculatorEnter your win probability and the offered odds to see the expected value of the bet, positive or negative.Goes with this
