Free betting calculators
The arithmetic OpenSlate runs on every DraftKings and Pinnacle player prop, as standalone tools. Each result has its own link, so you can share a calculation.
No-vig calculator: remove the vig from any two-way odds
Convert each side's American odds to an implied probability, then divide each by their sum. For -120 and +100 that is 54.55% and 50.00%, 104.55% together, so the no-vig probabilities are 52.17% and 47.83% and the fair prices are -109 and +109. Enter any two prices to get the fair odds and the book's margin.
Expected value (EV) calculator for sports bets
EV per $100 staked = chance of winning x profit - chance of losing x $100. At -110 (profit $90.91) with a 55% chance: 0.55 x 90.91 - 0.45 x 100 = +$5.00. The break-even chance at -110 is 52.38%. Enter a price and your probability, or a sharp book's two prices to use its no-vig probability.
Odds converter: American, decimal, fractional and implied probability
+150 American = 2.50 decimal = 3/2 fractional = 40.0% implied probability; -150 = 1.67 = 2/3 = 60.0%. Positive American odds are the profit on a $100 stake; negative odds are the stake needed to win $100.
Guides: Learn · Tonight's lines: Props. Arithmetic only, not betting advice. 21+.