American odds to cents: the 2026 Division Series prices, converted

A price of -180 and a price of 64 cents are trying to say the same thing. One of them hides the sportsbook’s cut inside the number. The other, on a prediction market, puts the cut in a fee and lets yes and no add up to a dollar. This weekend’s Division Series is a clean worked example, because all four series opened on October 3 with published American odds.

The matchups themselves are in the series-price note. This page is only the arithmetic.

The two formulas

For a favorite, the minus number is how much you risk to win $100. The implied probability, before anyone removes the margin, is:

minus odds ÷ (minus odds + 100).

-180 is 180 ÷ 280 = 0.643, or about 64 cents if a contract paid a dollar.

For an underdog, the plus number is how much you win if you risk $100:

100 ÷ (plus odds + 100).

+150 is 100 ÷ 250 = 0.40, or 40 cents.

The four series, on the morning of October 3

Sportsbook series prices, then the raw implied percent. The two sides of each series are both shown because the gap between them is the point.

• Brewers -180, Padres +150. 64.3% and 40.0%. Added together: 104.3%.
• Dodgers -230, Braves +190. 69.7% and 34.5%. Added together: 104.2%.
• Yankees -120, Rays +100. 54.5% and 50.0%. Added together: 104.5%. Plus-money even is a coin flip. -120 is only a small step off that.
• Guardians -140, White Sox +120. 58.3% and 45.5%. Added together: 103.8%.

None of those pairs add to 100. The extra three to five points is the book’s margin, spread across both sides. If you compare a 64-cent prediction-market contract to the Brewers’ -180 and call it “the same price,” you have skipped that margin. A fair comparison takes the margin out, or compares the prediction-market price to the de-vigged percent, not to the raw American number.

What the prediction market does differently

On Kalshi or Polymarket, a contract pays $1 if the thing happens and $0 if it does not. A trade at 64 cents is the market saying 64 percent, and the other side is the rest of the dollar, before fees. The fee is charged on the trade. It is largest when the contract is near 50 cents and smaller when the price is near 0 or 100. That is the opposite shape of a casual reading of a sportsbook, where people notice the juice most on big favorites because -230 looks harsh.

-230 is harsh. It is also 70 percent, not 90. The Dodgers being -230 to win a best-of-five is a real favorite and a long way from a sure thing. About three times in ten, the raw number says that series goes the other way, and that is before you argue about whether the price is too high.

A 90-cent price, since everyone is staring at one

The same conversion is why the House control market feels different from these baseball series. A price in the low-to-mid 90s is a favorite that should still lose several times in a hundred if the price is honest. It is not a -900 baseball monster, and it is not a lock. Cents make that easier to see than American odds do. 93 cents is 93 percent. The other side is 7 cents. You do not need a formula for that one.

Frequently asked

Do I divide -180 by 100? No. That is how people turn -180 into “1.8 to 1” and then misread it as an 80 percent chance. The denominator is the odds plus 100.

Which number should I trust, the book or the prediction market? Neither, automatically. Use them as two quotes of the same event. If they disagree by more than the fee and the margin, that gap is the only part worth a closer look.

Will these percents still be right tonight? No. They describe the sportsbook series prices on the morning of October 3, before the games. A Game 1 result moves the series price immediately. Recompute it. Do not memorize it.