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024 min read

Reading the price

American odds, and the probability hiding inside every one of them.

A price tells you two things at once: how much you win, and what the book thinks the chance is. Most people only ever read the first half, and that is exactly where the money leaks out.

Plus and minus

A plus price is what you win on a $100 stake. +150 wins $150 and returns your $100. A minus price is what you must risk to win $100. -150 means risking $150 to win $100. Nothing exists between -100 and +100, because a price in that gap is just the same number written the other way round.

The probability inside it

The price you get+150
Implied
40.0%
Wins on $100
$150
EV
+0.0%

Fair price is +150 (40.0%). At +150 you're being paid as though it were rarer than it is.

Every price converts to an implied chance, and that conversion is fixed arithmetic rather than anyone's opinion. Once a price is a percentage, two books quoting the same game can be compared directly — which is the entire foundation of everything else here.

PriceWins on $100Implied chance
+200$20033.3%
+100$10050.0%
-120$8354.5%
-250$4071.4%
Where you'll see this
Chiefs vs Bills
Josh Allen Over 1.5 Pass TD
Odds
-108
Fair
-123
EV
+6.4%
Grade
A+

The first cell is the price a book is offering. Everything else on the card is worked out from it.

The app does this conversion for you

Every card shows the offered price and the fair price side by side, both in American odds, so you are comparing like with like without doing arithmetic on your phone.

Check yourselfNothing is scored

1 of 3

What chance does +200 imply?

2 of 3

Why does no price exist between -100 and +100?

3 of 3

One book has -120 and another has +105 on the same side. What is the first thing to do?

Takeaway

A price is a probability with a payout attached. Read it as a percentage and every comparison gets easy.

+EVergreen

Terms from this lesson

Next · 03Why the board never adds up

Education, not betting advice. 21+. Gambling problem? Call or text 1-800-GAMBLER.