Enter both lines and prices. It tells you how to split your stake, what you make or lose if the middle misses, what you make if it hits, and how often it needs to hit to break even.
Odds can be American (+142, -112) or decimal (2.42). New to these? Read our guide to middles, or see today's live middles.
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You bet the over at a lower line and the under at a higher line, usually at different sportsbooks. If the result lands between them, both bets win. If it doesn't, one wins and one loses, so you usually lose a little or come out about even.
It's how often the middle has to land for the bet to pay off over time, given what you lose when it misses. If your estimate of the chance is below that number, the middle isn't worth it at those prices.
A result exactly on a whole-number line pushes that bet, so you get that stake back. The table counts those results for you.
No. Unless the prices also make an arb, a miss usually costs a small amount. That's the price you pay for the chance of winning both sides.