World Series Futures Odds on Kalshi: How Event Contracts Price a Repeat Champion

What is a 30.4c contract actually telling you?

If you pull up world series futures odds on an event-contract exchange and see the Los Angeles Dodgers at 30.4, that number is not a payout — it is a probability. Traders are collectively saying there is roughly a 30.4% chance the Dodgers repeat as champions. Translate that into the sportsbook language you already know and it comes out at +229. Same belief, two dialects.

That single conversion is the whole skill. Once you can move between cents and American odds in your head, a futures board stops looking like a list of payouts and starts looking like a forecast you can argue with. Here’s the process, using Kalshi’s board late in the 2026 regular season as the worked example.

Step 1: read the price as a probability first

On a prediction market, a contract settles at $1 (100 cents) if the event happens and $0 if it doesn’t. So the price in cents is the market’s implied probability. Buy the Dodgers at 30.4c and you risk 30.4 cents to collect a dollar. Nothing else needs decoding.

A sportsbook hides that same number behind a payout format. When you see +229, the implied probability is:

100 ÷ (229 + 100) = 30.4%

Going the other direction, from a contract price to American odds:

(100 − price) ÷ price × 100 → (100 − 30.4) ÷ 30.4 × 100 = +229

Memorise those two lines and you can compare any exchange quote to any sportsbook price in about five seconds.

Step 2: build the board and convert it yourself

Here is the field as it was priced on Kalshi with the postseason under way, alongside the American-odds equivalent produced by the formula above. Twelve teams, which is the full MLB playoff field.

One reason to run the conversion yourself: published boards contain errors. The version of this table circulating in the trade press paired the Brewers’ 17% with +880, which is the Yankees’ price and implies about 10.2%, not 17%. Its Cubs line (+2226) corresponds to 4.3% rather than the 4.2% shown. Neither is a conspiracy, just rounding and copy-paste, but if you were shopping for value on a mispriced row you’d be chasing a typo.

Prices also move. The same report headlined the Dodgers at 30.8% while its table showed 30.4%. On a live exchange during the playoffs, that is normal: a quote is a snapshot, and last-traded price, best bid and best ask are three different numbers.

Step 3: add the column up

Now do the thing almost nobody does. Sum the implied probabilities: 30.4 + 17 + 11 + 10.2 + 7 + 6.3 + 5.7 + 4.2 + 4.1 + 4 + 3.6 + 2.3 = 105.8%.

Exactly one of those twelve teams will win, so the true probabilities must sum to 100%. The extra 5.8 points is the market’s cost of doing business, showing up as bid/ask spread, rounding to the nearest tenth of a cent, and exchange fees rather than as a bookmaker’s margin. It is the event-contract version of the overround.

Why that matters: futures boards at sportsbooks routinely carry a much heavier margin than a two-way point spread market, because tying up money for months is expensive and the book wants compensation for it. When you compare a 105.8% sum against a sportsbook’s futures board that sums far higher, you are looking at the real difference between the two products. Not the drama of “prediction markets versus betting” — just how much of your stake gets eaten before the first pitch.

Step 4: work out what the price is pricing in

A number like 30.4% is the residue of a hundred separate judgements. With the Dodgers, the market was digesting some genuinely bad news and some genuinely good news at the same time:

• Shohei Ohtani’s health. His second half dipped as he handled knee and bicep problems, Los Angeles placed him on the injured list on 9 September, and he was not pitching in the postseason. Across his final five games he hit .238 with eight strikeouts and no home runs, though he did get hits in four of the five.
• Bullpen attrition. Blake Treinen’s right shoulder gave out, ending his season after a 4-1 record.
• Rotation upgrade. Tarik Skubal, acquired from Detroit in August, struck out 10 and allowed no runs over seven innings in a 2-0 win over the Giants.
• Lineup questions. The offence stalled over the summer, with Freddie Freeman leading the team at .288 and Mookie Betts at .257.
• Bracket path. Los Angeles was set to face the winner of Phillies vs Braves, both of whom the market priced under 6%.

Put those together and the 30.4% quote makes sense as a compromise: the deepest roster in the field, an easier first opponent than most, and real injury risk at the top. If your own read on any of those inputs differs sharply from the consensus, that gap is your thesis. If it doesn’t, you’re paying the spread to agree with the crowd.

Step 5: understand what you are trading on, not just the number

Kalshi operates as a federally regulated exchange under the Commodity Futures Trading Commission, and its sports event contracts have been contested by several state gaming regulators who view them as wagering. That dispute is unresolved and worth following, because it determines which products stay available in which states.

Mechanically, the trading structure differs from a fixed-odds bet in ways that matter:

• You trade against other participants, not against a house that sets the line.
• You can usually sell a position before settlement, so a Dodgers contract bought at 30.4c can be closed at 45c or 12c depending on how October goes. A pre-season futures ticket at a sportsbook generally can’t be re-priced unless the operator offers a cash-out.
• Liquidity, not generosity, sets how tight the price is. Thin markets have wide spreads, and a wide spread is a cost even when the midpoint looks fair.

The limit of implied probability

A 30.4% favourite loses roughly seven times in ten. That is what the number says, and it is the part people forget the moment a team is called “the favourite”. Being the best-priced team on a 12-team board is not the same as being likely to win.

Implied probability is also not a forecast you can verify from one outcome. The only honest test is across hundreds of markets, and even then the built-in margin means the average participant loses over time. Event contracts remove the bookmaker, not the maths. Treat any position as money you are prepared to lose, use deposit and loss limits where your venue offers them, and if tracking a market stops feeling like analysis and starts feeling like chasing, take a break. Support services for problem gambling are free and confidential in most jurisdictions. Nothing here is betting or investment advice, and these markets are for adults only.

Quick answers

What are event contracts?

Tradeable contracts on the outcome of a defined future event. They settle at $1 if the event happens and $0 if it doesn’t, so the price in cents equals the market’s implied probability.

How do I convert American odds to implied probability?

For positive odds: 100 ÷ (odds + 100). For negative odds: odds ÷ (odds + 100), using the absolute value. So +229 is 30.4% and −150 is 60%.

Are prediction market prices the same as betting odds?

They express the same information in a different unit, but the pricing mechanism differs. Exchange prices come from participants trading with each other, sportsbook prices come from an operator who builds in a margin and manages its own liability.

Why don’t the probabilities on a futures board add up to 100%?

Because of spread, fees and rounding. The Kalshi board above summed to 105.8% across the 12 playoff teams, and the excess is what the market costs to use.