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Parlay and prop guides
Short, practical guides for checking and pricing NBA and NFL slips. Start with the bet slip checker, then dig into the math.
How to check a parlay before you bet
A 7-step pre-bet check you can run on any NBA or NFL slip in a few minutes.
How to fix a parlay with a bad leg
Drop it, swap the line, swap the player or split the slip: what each fix does to your price.
Same game parlay correlation, explained
Why legs from one game aren't independent, and how books price that into an SGP.
How to read prop odds and implied probability
Turn any American price into the chance it needs to hit, with a cheat-sheet table.
What is the vig? Finding no-vig fair odds on props
Strip the book's margin from an over/under pair and see how it compounds in a parlay.
How many legs should a parlay have?
The math of adding legs: payout, break-even chance and how the margin stacks up.
How to load a slip into FanDuel or BetMGM in one tap
From a screenshot to a filled FanDuel or BetMGM bet slip, and what to check before you confirm.
Model picks, not locks. No checker can tell you a slip will win; it can only show you the price, the math and what changed. 21+ only. If betting stops being fun, call 1-800-GAMBLER or read our responsible gaming page.