Calculator 01
Odds, probability and payout
American odds imply a break-even probability. Enter the price and stake to see what a win returns.
At -110, break-even is 52.38%. Winning 50% at that price loses money.
Free betting math tools
Turn the price into evidence.
Convert American odds, remove a two-way market's margin, and measure closing-line value without a spreadsheet.
Calculator 02
Two-way no-vig probability
Normalize both sides so their probabilities total 100%. This removes the posted margin; it does not prove either side is correctly priced.
A -110/-110 market carries 104.76% raw probability and normalizes to 50% per side.
Calculator 03
Closing-line value
Compare the exact release price with the same outcome's near-start price at the same sportsbook.
Positive means the release beat the close. Line changes, different books and different outcomes are not valid comparisons.
How OddsFoundry uses these numbers
Model probability becomes a fair price. The available price determines the implied probability and the gap between the two is the estimated edge. After a live release, the close provides a second, outcome-independent check on whether the original price was strong. ROI still matters, but CLV can become informative before a modest sample of wins and losses settles.
Go deeper with implied probability and vig, fair price versus market price, and closing-line value.