Question 1

Why take the sportsbook's cut out?

Accepted Answer

Both prices are padded so the book keeps a cut either way. Take the padding out and what's left is the market's own read on each side's chance — the number worth comparing every other sportsbook's price against.

Question 2

Which method does this use?

Accepted Answer

The standard one: both sides are scaled down in proportion until they add up to 100% (the multiplicative method). Two others, power and additive, shade heavy favorites differently.

Question 3

Is this the true chance of winning?

Accepted Answer

It's the market's best read at that moment, and no more. Prices from Pinnacle and Betfair Exchange give the closest read, because they take a small cut and handle large bets.

Question 4

Does this work for a market that can end in a draw?

Accepted Answer

Not here — this handles two-sided markets. For a soccer match or anything else with three results, use the advanced fair-price tool, which takes all three prices.