Odds Formats
Every price on AllTop can display in one of three formats: Percent, American, or Decimal. They're the same number displayed three ways, and Percent is the default because a prediction market price literally is a probability.
The examples below come from the World Cup tournament winner table on AllTop, shown in all three formats with an explanation of how to use the settings.
How to use the format settings
The Format toggle sits above the table (%, Am., Dec.) and appears alongside odds displays across the site. Your choice is remembered in your browser, so it persists between visits on the same device. If you're signed in, the preference saves to your account instead and follows you across devices. You can toggle between the three different formats at any time. Signing in and its other benefits are covered in what an account unlocks.
Percent format is the default setting
The percent format is the default setting for nearly all markets. The price maps directly to the market's implied probability: Spain's aggregated 58.7% means traders are collectively pricing Spain at roughly a 59 in 100 chance to win the tournament. The green +0.6pp under the number is the 24-hour move — the market's estimate of Spain rose six tenths of a point. If probabilities are new territory, start with our primer on implied probability.
Decimal format
Decimal odds answer: for every dollar staked, how much comes back in total if the outcome hits? The conversion is one divided by the probability. Spain at 58.7% converts to 1 ÷ 0.587 = 1.70, which is what the table shows with the Dec. toggle on.
Check it against the contract math. Stake $25 on Spain at 58.7¢ and you hold about 42.6 contracts. If Spain wins they pay $42.59 — and $25 × 1.70 comes to the same $42.50-and-change. Your profit is about $17.60; the decimal figure always includes your stake. Lower probability means a bigger decimal number, since a longshot pays more per dollar: Argentina at 41.2% shows 2.42.
American format
American odds split into two cases around the 50% line, and the tournament table shows both at once.
Favorite (above 50%): the number is negative and tells you how much you'd risk to win $100 in profit. Spain at 58.7% converts to −(58.7 ÷ 41.3) × 100 = −142. Proof from the contract: $142 buys 242 contracts at 58.7¢, which pay $242 if Spain wins — $100 of profit.
Underdog (below 50%): the number is positive and tells you the profit on a $100 risk. Argentina at 41.2% shows +142: the $100 buys about 242 contracts, which pay roughly $242 if Argentina wins — $142 of profit.
At exactly 50%: the two branches meet at 100 — risk $100 to win $100 — displayed as −100, the coin-flip price. Egypt's Polymarket cell in the screenshot shows exactly this.
Spain at −142 and Argentina at +142 in the same table is the symmetry worth noticing: the market prices Spain's edge over Argentina, and the two American numbers mirror it from opposite sides.
One rounding note: conversions run on the unrounded price, so a hand calculation from the displayed percent can land a point off the displayed odds. Argentina's 41.2% works out to +143 by hand; the table shows +142 because the underlying price is closer to 41.3¢.
Reading low-volume rows
Egypt's row is the caution case. The aggregated number reads 49.1% (+104, 2.04), but look across the row: $0 volume, no trend line, a 49-point spread, and the venue cells show resting asks of 1¢ on Kalshi and 100¢ on Polymarket. Nobody has traded this market — those aren't forecasts, they're unfilled orders sitting at the extremes. Before reading any odds as a probability, check the volume and spread columns; a number without volume behind it is a placeholder, not a price. Volume and the other row metrics are covered in what volume, trades and open interest mean.
Converting odds back to a probability
Odds you see elsewhere convert back to a probability in one step:
Positive American: 100 ÷ (odds + 100). Argentina at +142 is 100 ÷ 242 = 41.3%.
Negative American: odds ÷ (odds + 100), using the number without the minus sign. Spain at −142 is 142 ÷ 242 = 58.7%.
Decimal: 1 ÷ decimal. Argentina's 2.42 is 1 ÷ 2.42 = 41.3%.
This is the fastest way to compare a sportsbook line against a prediction market: convert both to percent and the gap is the disagreement.
Choosing the format that works best for you
Use the one your intuition is trained on. If you come from sports betting, American will feel native. If you come from European bookmakers or you think in payout multiples, Decimal. If you're here for the forecasting, stay on Percent, because it keeps the central insight of prediction markets in front of you: the price is the probability, and when the price moves, the market's estimate of reality just changed.
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Cheryle brings 20 years of experience in research and marketing to AllTop. She previously led content and growth at Catena Media and now oversees prediction market research and editorial methodology across the publication.