just now · prices from Kalshi
Every multi-outcome market on Kalshi, ranked by how much it costs to back the entire field. A fair book adds up to 100. Everything above that is the house's margin, and you pay it whether you win or lose. This is the number the site is named after and, as far as we can find, the only place it is published.
The bar is the margin, not the price. Read it as: for every dollar that eventually pays out on this market, this is roughly what the house keeps for running it. Wide is not the same as crooked, and the last section explains why.
Take every outcome in a market and add up what it costs to buy each one. If the total is 100, the prices are a clean probability distribution and the house is taking nothing. If the total is 118, then backing the whole field guarantees you spend $1.18 to get $1 back, and those 18 cents are the margin. You are paying it on any single bet too, spread across the prices you see, which is why it is worth knowing before you trade rather than after.
A wide book is usually not greed, it is thinness. A market with twenty runners and four thousand dollars in it has nobody standing ready to take the other side, so the quotes drift apart and the sum balloons. That is why the open interest is printed next to every row: a 140% book on a market with real money in it is a different animal from a 140% book on one with none. The useful habit is comparing a market against the typical one above rather than against 100, and treating anything in the brutal band as a signal that you are the only person in the room.
Our sums use the ask, which is what you would actually pay, and only complete fields where every outcome has a live two-sided quote. Kalshi publishes none of this and neither does anyone else we can find, which is the entire reason this page exists. If you spot a number here that looks wrong, it goes on the corrections page.