Excerpt: Everybody argues about which side to take — almost nobody checks what the exchange charges for the privilege, and there's a lever sitting in plain sight that cuts that charge by three quarters.
Back to school, back to school. I've got my lunch packed up, my boots tied tight, and a PDF of Kalshi's official fee schedule open in another tab, which is the least Billy Madison sentence ever assembled by a human being.
Here's the curriculum — in Kalshi 101 you learn what a contract is, a thing that pays a dollar if you're right and nothing if you're wrong, priced in cents that double as a probability. In Kalshi 201 you learn to read a board: how prices across one event relate to each other, why a division market and a playoff market can flatly contradict each other, where the crowd is standing and where it isn't.
Kalshi 301 is about what it costs to be right.
This is the class everybody skips. There are no takes in it. Nobody has ever been quote-tweeted for knowing a fee formula. And it is, without much competition, the highest-ROI hour you can spend on this exchange — because a sharp handicapper with sloppy execution and a mediocre handicapper with clean execution land in roughly the same place at the end of a season, and only one of them had to be right about football.
The thesis, up front, so you can bail if you already know it: the fee is a parabola, it peaks at 50 cents, and there's a lever sitting in plain sight that cuts it by 75%. Almost nobody pulls it. I wasn't pulling it consistently until I sat down and did this math.
There's a lab at the end on the biggest market in America this week. Bring a calculator, or don't — I already did it.
Prerequisites
You should know what a bid and an ask are, and you should understand that the number on the screen is the market's estimate rather than the truth — we are only here for the spots where we think that estimate is wrong, and the size of the disagreement is the entire business. You should also be at peace with the fact that a cheap ticket misses more often than it hits even when the edge is real: deciding a 30-cent contract is worth 36 is a good day's work, and most of those tickets still die. If any of that is news, go take 101 and come back.
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Lecture 1: The Fee Is A Parabola
Here's Kalshi's actual published formula, from their fee schedule:
Taker fee = round up (0.07 × contracts × P × (1 − P)) Maker fee = round up (0.0175 × contracts × P × (1 − P))
Set that aside for one second and just look at the shape. P × (1 − P) is a parabola. It equals zero at both ends and maxes out in the exact middle. Which means the fee on a Kalshi contract is largest, in raw cents, at 50 cents — and it falls away in both directions.
| Price | Taker fee per contract | Maker fee per contract |
|---|---|---|
| 5¢ | 0.33¢ | 0.08¢ |
| 10¢ | 0.63¢ | 0.16¢ |
| 25¢ | 1.31¢ | 0.33¢ |
| 40¢ | 1.68¢ | 0.42¢ |
| 50¢ | 1.75¢ | 0.44¢ |
| 65¢ | 1.59¢ | 0.40¢ |
| 75¢ | 1.31¢ | 0.33¢ |
| 90¢ | 0.63¢ | 0.16¢ |
The single most-fee'd contract on this exchange is a coin flip — longshots are cheap in raw cents, heavy chalk is cheap in raw cents, and the 50/50 sitting in the middle, where most of the volume lives and all of the arguing happens, carries the fattest toll on the board.
One footnote on the rounding, because it bites in a specific place. Fees round up to the next cent per order, not per contract. Buy one contract at a penny and the math says you owe seven hundredths of a cent, which rounds up to a full cent — you just paid a 100% markup. Buy a thousand of them and the fee is 70 cents total, which is 0.07¢ each and completely painless. Tiny orders on penny contracts are the worst value on the board. The same trade in size is fine.
Lecture 2: The Same Fee Gives Two Different Answers
Here's where it gets interesting, and where I think most people's intuition is wrong.
"The fee peaks at 50¢" is true in cents. But nobody experiences a fee in cents. You experience it as a bite out of your stake, or as a bite out of your winnings. Those are two different questions and they have opposite answers.
| Price | Fee as % of what you risk | Fee as % of what you'd win |
|---|---|---|
| 5¢ | 6.65% | 0.35% |
| 10¢ | 6.30% | 0.70% |
| 25¢ | 5.25% | 1.75% |
| 50¢ | 3.50% | 3.50% |
| 75¢ | 1.75% | 5.25% |
| 90¢ | 0.70% | 6.30% |
Read those columns going opposite directions.
Longshots are brutally expensive relative to your stake. A nickel contract charges you 6.65% of everything you put up. You are down almost 7% the instant the order fills. But that same fee is a rounding error against the payout, so if the thing hits, you barely notice.
Favorites are the mirror image. Buying at 90¢ costs you 0.7% of your stake, which barely registers — but it's eating 6.3% of the only money you stood to make. You risked 90 cents to win 10, and the exchange took two-thirds of a cent of that 10.
Fifty cents is the one place they're equal, at 3.5% each, which is also where the raw cent cost is highest. The middle of the board is expensive by every measure at once.
Lecture 3: The Fee Is Your Minimum Edge
This is the sentence I want you to steal and use forever.
To break even on a Kalshi trade, you have to be right by more than the fee. Not right. Right by a margin. And the margin required is exactly that parabola: 1.75 cents at midboard, about a third of a cent at a nickel.
Run it against a real situation. Last week I found what I thought was a genuine mistake — a player's tournament price implied he was a coin flip in a final against a man he'd lost to five straight times, and I made him about seven cents too expensive. Real edge, defensible math.
To collect it I'd have had to buy the NO side at 65 cents, where the taker fee is 1.59¢. That's 23% of the edge gone before a ball is struck, on a seven-cent read I'd assembled from estimates I'd have happily argued were plus or minus three. So I wrote it up, called it a fun fact, and passed.
An edge you can't clear the fee with is a hobby. Write the fee down before you write the ticket, and if your edge doesn't comfortably exceed it, the correct play is to find a cheaper expression of the same opinion or leave it alone.
Lecture 4: The 75% Discount Nobody Takes
Go back and look at that second column in Lecture 1. The maker fee is 0.0175 against the taker's 0.07. One quarter.
A taker is somebody who hits an existing order — you click the ask, you're filled instantly, you pay full freight. A maker is somebody who rests an order and lets the market come to them. Same contract, same event, same opinion. Four times the fee for being in a hurry.
Fifty Cent put out a song about this in 2003 and called it "Patiently Waiting," which as far as I can tell remains the only sound execution advice ever delivered over a Dr. Dre beat.
And that's before you account for the fact that the resting order is also getting a better price, because you're bidding inside the spread instead of paying it.
Here's what those two effects do together, using a live market. I'll do the full lab in a minute, but take the biggest contract on the exchange this week — the Fed hiking 25 basis points, bid 54¢ and offered at 55¢:
| Approach | Price | Fee | Effective | American odds |
|---|---|---|---|---|
| Cross The Spread (Buy At 55¢) | 55¢ | 1.73¢ | 56.73¢ | -131 |
| Rest A Bid (Work 54¢) | 54¢ | 0.43¢ | 54.43¢ | -119 |
Twelve points of American odds. Same market, same side, same afternoon. The entire difference is whether you were willing to wait.
Do it on the other side of that market and it's the same story in reverse: crossing at 46¢ gets you +110, resting at 45¢ gets you +120.
Scale it up and it stops being cute. Deploy $10,000 at midboard prices and you've bought about 20,000 contracts. All taker, that's $350 in fees. All maker, $87.50. You saved $262.50 by using limit orders, which is a real number that arrived with zero improvement in your handicapping.
Waiting is also a skill I've involuntarily acquired this year. Once you've spent 20 minutes frozen on a couch because moving your arm would wake a five-month-old, letting a limit order sit for an hour stops registering as a sacrifice.
The catch is honest and you should hear it: a resting order might not fill. Sometimes the market runs away and you miss it entirely. That's a real cost, and there are moments — a live game, a headline breaking, an overnight panic print evaporating in front of you — where crossing is correct because the price is the opportunity. Patience is the default. Urgency is the exception, and you should be able to say out loud why this one qualifies.
Lecture 5: Read The Board Before You Read The Price
One more habit, and this one takes ten seconds.
Before you evaluate any single contract, add up the whole event. In a market where exactly one outcome happens, the prices should sum to 100. Whatever they sum to above 100 is the toll, and the toll varies enormously from board to board.
| Board | Sum of asks | Read |
|---|---|---|
| Fed Decision, Two Live Strikes | 101 | Beautifully tight. Trade it. |
| An NFL Division Market | 106 | Normal. Fine. |
| A Baseball Pennant Market | 112 | Wide. Work limit orders only. |
That single number tells you how hard the board is fighting you before you've formed a single opinion. On a 112 board, crossing the spread is a decision you should have to justify.
And while you're up there, check the volume. A price is only information if somebody had to defend it. I've watched a championship contract with 5.1 million in volume sit next to the same team's pennant contract with 749,000 — and the two prices flatly disagreed with each other. The quiet one was the opportunity, and the volume column is what told me which one was quiet.
Pop quiz, and it will be on the exam: in a four-outcome market, before you buy three of the outcomes to cover the field, price the single NO on the fourth one. In an NFL division market last week, buying NO on the favorite cost 45 cents while legging the other three cost 51 — and legging meant paying three separate fees, dragging the true cost to about 54. Six cents of better structure, plus two fees you never had to pay, for asking one question.
Lab: The Most-Searched Story In America, Priced
Time to use it on something live.
The number one search term in the country right now is oil prices, on Brent touching $100 a barrel with the Middle East in turmoil. That story has exactly one tradeable expression: the Federal Reserve meets Wednesday, Sept. 16.
The Kalshi board:
| Outcome | Price | Volume |
|---|---|---|
| Hike 25 Bps | 54¢ | 7.79M |
| No Change | 46¢ | 16.57M |
| Hike More Than 25 Bps | 2¢ | 9.75M |
| Cut 25 Bps | 1¢ | 7.30M |
| Cut More Than 25 Bps | 1¢ | 1.17M |
Now run the syllabus on it.
Lecture 5 first, always. The two live strikes bid 99 and ask 101. That is an exceptionally well-made market, and the volume behind it is enormous. Nothing about this board is trying to rob you.
Lecture 1 and 2. Both live outcomes sit at 54 and 46 — the apex of the parabola. This is the single most expensive place on the exchange to have an opinion, at 1.74¢ a contract, and it's costing you 3.2% of your stake and 3.8% of your profit simultaneously. The most-searched story in America routes traffic directly into the priciest real estate Kalshi sells. Nobody planned that. It's just where coin flips live.
Lecture 3. Your minimum edge here is 1.74 cents. So the question is no longer "will they hike." It's "am I more than two cents better than a market with 24 million contracts of combined volume across the two live strikes." Answer that honestly before you touch it.
Lecture 4. And if the answer is yes, do not click the ask. Twelve points of American odds are sitting there for the price of a limit order and some patience.
I'm not giving you a side on the Fed today, because I don't think I'm two cents better than that board and I'm not going to pretend otherwise for the sake of a card. What I'll say is that a market pricing a hike as the favorite, six days out, with crude at $100, is the most interesting thing on this exchange — and if you're going to be involved, be involved at 54 and not 55.
The Cheat Sheet
Tape this to something.
| Rule | The number |
|---|---|
| Taker Fee | 0.07 × P × (1 − P), rounded up per order |
| Maker Fee | 0.0175 × P × (1 − P) — one quarter |
| Most Expensive Price On The Board | 50¢, at 1.75¢ a contract |
| Worst Fee As A Share Of Stake | The longshots — 6.65% at a nickel |
| Worst Fee As A Share Of Profit | The chalk — 6.30% at 90¢ |
| Your Minimum Edge | Whatever the fee is. Write it down first. |
| Cost Of Impatience | Roughly 10-12 points of American odds at midboard |
| Board Sum Above 100 | The toll. Above ~110, work limits only. |
| Before Legging A Field | Price the single NO first |
| Before Calling It An Edge | Check the volume column |
Two caveats, because this is a class and not a brochure. Kalshi runs a reduced taker rate of 0.035 on their S&P 500 and NASDAQ-100 markets, so the index products cost half of everything above. And fee schedules get revised — mine came straight from Kalshi's published document, but check the current version before you build a strategy on a decimal point I typed in September.
More on this: Five Snaps, Ten Cents: The Sam Darnold Ripple Effect On Kalshi's NFC Board · NBA Championship Odds: Why The 76ers Are Only An 11 Percent Team · The Forecast Is Not The Price On A Kalshi Weather Market · What Can You Bet On Kalshi? Every Category, And How Often Each Settles · Kalshi Weather Trading: '100 In Phoenix' Isn't A Trade
Final Thoughts
None of this makes you right more often. That's the uncomfortable part. Lecture 4 doesn't improve your read on a football game by a single percentage point.
What it does is stop the leak. If you make a hundred trades a year and you're a genuinely good handicapper, the difference between crossing every spread and working every limit is the difference between a decent year and a flat one — and it shows up whether your picks were any good or not. Execution is the part of this you control completely, which makes it the strangest thing in the world to ignore.
The permanent two, unchanged. Most tickets lose. Even when the edge is real, a 46-cent contract is going to miss more often than it hits — an edge moves your win rate, it doesn't flip the coin — and knowing the fee schedule cold does not change that one bit. And size like an adult — quarter and half units, no chasing, no hero sizing because you finally understand a formula. A parabola has never once covered a bad bet.
Class dismissed. Office hours are wherever you find me arguing about a two-cent edge.
— Lindy
Sources: Kalshi fee schedule (official PDF) · Kalshi Fed decision market · Google Trends US daily feed
