Find the edge.
Size the bet.
Four tools, one workflow. Strip the vig off a line, convert any price, stack a parlay, and size your stake with Kelly — and hand the fair number from one tool straight to the next.
Enter both sides of a market to strip the book's margin and reveal the fair, no-vig price. Then send a side straight to Kelly as your win probability.
Prefer the focused version? Open the standalone No-Vig Calculator →
Type a price in any format — American, decimal, or fractional. Every other format, the implied probability, and the break-even win rate update live.
Prefer the focused version? Open the standalone Odds Converter →
Add each leg in any format. This multiplies them into one price and shows the true probability the whole ticket cashes.
Prefer the focused version? Open the standalone Parlay Calculator →
Enter the odds and your true win probability to get the optimal stake. Half-Kelly is highlighted — full Kelly is the ceiling, not the recommendation.
Prefer the focused version? Open the standalone Kelly Calculator →
01How the four fit together
These aren't four separate gadgets — they're one process. De-vig turns a sportsbook line into the fair probability behind it. Convert translates any price and shows the break-even rate you have to beat. Parlay stacks legs and exposes how the vig compounds. Kelly takes your edge over the fair price and tells you how much to bet. The whole point of having them in one place is the handoff: de-vig a market, send the fair price into Kelly, and size the bet without re-typing a thing.
02The one workflow worth memorizing
Strip the vig to get the market's fair read. Form your own honest probability for the side you like. Bet only when your number beats the fair number — that gap is your edge. Then size it with half-Kelly, never full. Most losing bettors skip straight to the stake; the edge is everything that happens before it.
03One honest caveat
Every number here is only as good as the inputs you feed it. De-vigging assumes the two prices you enter are the real market; Kelly assumes your probability estimate is honest. Garbage in, confident-looking garbage out. Use these to structure your thinking, not to manufacture an edge that isn't there.
Betting calculator FAQ
The best calculator depends on the job: de-vigging a line, converting odds, pricing a parlay, or sizing a bet. This suite puts all four in one place and connects them — strip the vig off a market, then push the fair price straight into the Kelly sizer without re-typing. Each tool is also available as a focused standalone page.
They're one workflow. The no-vig calculator turns a sportsbook line into its fair probability. The odds converter translates any price and shows the break-even rate. The parlay calculator stacks legs and exposes the compounded vig. The Kelly calculator takes your edge over the fair price and sizes the stake.
Expected value is the average result of a bet if you could place it many times. A bet is +EV when your true win probability beats the price's implied probability — that gap is your edge. The whole point of this suite is to find and measure that gap: de-vig to get the fair number, then bet only when your read beats it.
No. Every tool runs entirely in your browser. Nothing you type is sent anywhere or stored — enter odds, get results, done. There's no signup, no login, and no data collection on any calculator here.
Yes, all of them, with no limits. Enter as many markets, parlays, or bets as you want. The tools are supported by ads, not fees.