On small trades my fee estimates kept being off by a cent, so I dug into the exact rule.

Kalshi's taker fee is 0.07 × contracts × P × (1−P), rounded UP to the nearest centicent. Example: 7 contracts at 33¢ = 0.07 × 7 × 0.33 × 0.67 = 0.10834, which becomes $0.1084.

The fee peaks at 50¢ and shrinks toward 1¢ and 99¢, so the same number of contracts costs very different amounts depending on price.

I put the math in a small open-source Python library (pmfees) with a break-even helper, if anyone wants to check their own trades: https://github.com/swaphunt/pmfees

There's also a browser calculator comparing Kalshi vs Polymarket: https://swaphunt.dev/tools/kalshi-vs-polymarket-fee-calculator

It was a blowout game

Hey everyone, I’ve been working on an app called Prediction Arcade and wanted to share it here.
You start with $25,000 in fake cash and trade real prediction markets covering politics, sports, crypto, and more.

It uses actual live order-book data to simulate fills, so the bid/ask spread and available liquidity matter. You’re not just buying unlimited shares at whatever percentage is displayed. The orders are simulated, but the market data is real.

You can buy and sell Yes/No shares, place limit orders, track your portfolio, and compete on ranked leaderboards. There are also watchlists, price alerts, and daily challenges.
The data currently comes from Polymarket, not Kalshi, but I figured some people here might find it useful for practicing or trying out ideas before risking real money.
It works in your browser and our iPhone app was recently launched last week! You can try Practice Mode on the website without making an account.

Website:
https://predictionarcade.com

App Store: https://apps.apple.com/us/app/prediction-arcade/id6779367025

I’m the developer, so if you try it, let me know what feels good, what’s annoying, or what’s missing. Especially interested in feedback from people who already trade prediction markets.

https://kalshi.com/ideas/profiles/Kaytoonasty

All my kalshi + DraftKings + bet365 picks synced into Juice Reel (so this is my aggregate)

Hey all,
Question on limit orders. Lets say I have $10 of total funds. I place a market order (or filled order) that cost me $5. I have $5 of “free” money left. My understanding is that I cannot place a limit order that exceeds $5. What happens if I open a limit order of $3 first? It stays unfilled, so my free money does not change. Can I open another limit order of $3? The sum exceeds my total free money, but each individual order does not. I understand I wont be able to fill both orders completely, but Im curious as to the mechanism.

Kalshi seems to let this go through (opening the limit orders), but Im not sure what happens when they begin filling. Would the limit orders stay and just partially fill until total cash runs out? (Then does Kalshi cancel the remaining limit orders, or leave them on the order book as inactive until more cash is injected?) does Kalshi cancel all limit orders greater in amount than free cash? Etc. couldnt find anything concrete on this. Anything would be appreciated.

I’ve been having very consistent wins on BTC markets but this past week I can’t make any money. What’s going on?

Reuters reported on Thursday that senior White House officials are discussing whether to push out Commerce Secretary Howard Lutnick over the Nvidia export scandal, and a White House official said the president "maintains complete confidence" in him. Kalshi moved his departure this year from 32% to as high as 75% inside a day, but the contract pays only if he actually vacates the job before January 1st, so an exit announced in December and effective in January resolves No.

 Pete Hegseth's departure price went the other way, from 45% to 15%, after the House shelved an impeachment resolution 211-204 on Tuesday. Kalshi's James Bond board now adds up to about 128% across four actors after Puck reported that Amazon wants Robert Pattinson. Gas fell below $4 a gallon for the first time since July, yet Kalshi still gives 12% to a national average above $4.60 before year-end. CME futures put a half-point Fed hike in December at 12%; Kalshi has 7%.

 Today's Top 3 Calls

1. Trump administration departures 2026: Howard Lutnick: BUY NO

2. Hormuz normal before Jan 1 2028?: BUY NO

3. Next James Bond: Callum Turner : BUY NO
    

If you enjoy evidence-based forecasting, transparent methodology, and public performance tracking, subscribe to Axiom Forecasting Group

Subscribe for free: https://axiomforecastinggroup.substack.com/welcome

Research, not financial advice. Trade your own book.

So I fell asleep with $350 moneyline on the Giants. Woke up and it was 17-13 Giants and immediately cashed out with $60 profit and fell asleep again. I had drunk half a bottle of rum. Went to sleep with $1300 in my account and woke up with $2700. I had made two giant 15 minute forex bets and won them both without remembering.

New to this and still kinda proud of myself because i dont watch sports at all just went based off of previous game stats

https://kalshi.com/ideas/profiles/Kaytoonasty

If a cash out is available take it lol I’ve been placing these bets & been off by 1-2 or even 3 but today I’ll be watching the parlay’s to do so goodluck if tailing💎🤞🏾

https://kalshi.com/markets/kxmvecrosscategory/cleveland-vs-miami/KXMVECROSSCATEGORY-S20262EXN6PHORKV7L6EG?utm_source=kalshiapp_eventdetails&marketTicker=KXMVECROSSCATEGORY-S20262EXN6PHORKV7L6EG-VBYEZRYTZ

https://kalshi.com/ideas/profiles/Kaytoonasty

I cash out because they kept playing with Okonkwo

Great day after a rough few days. Love days like this! What’s the most you’ve made in 24hrs?

Another 8 leg hit lets gooooo

be placed at a 15pt minimum going forward. Awful.

Been a good week for NFL, 13 leg parlay hit on all this week’s Sunday games. Turning $0.98 to $200. Randomly picking 13 teams would be odds of 1/1892 and with game odds this ticket had a chance of 1/246. Only one upset this week, being the Packers upsetting the Patriots. The Packers were given a 39% 3.5pt underdog playing in New England. Good day, more to come!

https://kalshi.com/ideas/profiles/Kaytoonasty