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OddsAssist Kalshi calculators: what they do, what they cost, where they stop
Last checked 2026-09-08
OddsAssist Pro is a sports betting odds site that added a prediction market calculator set: four Kalshi tools (fee, payout, combo, odds converter) and 14 more for Polymarket, Robinhood, Crypto.com, DraftKings Predict, Fanatics, FanDuel Predicts, OG.com, Underdog and Novig. All of them open without a login.
The Kalshi fee and payout calculators are the reason to bookmark it. They take an order type, a price in cents and a contract count, and return the fee, total cost, net profit if right, net loss if wrong, ROI and a break-even price that includes the fee.
What it does
The Kalshi Fee Calculator has three inputs: order type (Taker or Maker), contract price from 0 to 100 cents, and number of contracts. It outputs the per-trade fee, which the page labels as a 0.07% to 1.75% range, the cost per contract with fee, and total cost.
The Kalshi Payout Calculator takes the same inputs and adds the full position view: contract cost, taker fee, total invested, gross payout, net profit and ROI if you are right, net loss if you are wrong, implied probability, fee-inclusive break-even price, and the $1.00 gross payout per contract.
- Kalshi: Fee Calculator, Payout Calculator, Combo Calculator, Odds Converter
- Polymarket: Fee, Payout, Combo and Odds Converter, with taker fees of 0.05% to 2.5% and a 1.25% maker rebate, stated as applying to the U.S. version of Polymarket
- One-off fee or payout calculators for Robinhood, Crypto.com, DraftKings Predict, Fanatics Markets, FanDuel Predicts, OG.com and Underdog Predicts
- 21 sportsbook calculators on the same index page (arbitrage, hedge, Kelly, no-vig, parlay, CLV and others)
Pricing
The calculators load and run without signing in. The site offers a free sign-up for its odds data and promotes a Prediction Markets Pro tier, but no price for that tier appears on the calculator pages or the home page we fetched.
Venues and data
Each calculator is bound to one venue's fee model. The Polymarket pages state that the fees apply to the U.S. version of Polymarket. The FanDuel Predicts page describes a 2% payout fee charged only on winning positions.
No live prices are pulled in. You type the contract price yourself.
Where it falls short
The Kalshi fee page shows a 0.07% to 1.75% range but does not show the formula that places a given price inside it, so you cannot audit the number it returns without going to Kalshi's own fee schedule.
The site is sportsbook-first. The calculator pages carry a Polymarket deposit bonus promotion, and there is no cross-venue comparison tool: to compare a Kalshi fee with a Polymarket fee you open two pages.
Who should use it
A Kalshi trader who wants the fee-inclusive break-even for one order, and a trader active on the newer venues (Robinhood, Crypto.com, Fanatics, Underdog) that few other calculator sites model.
Questions about OddsAssist Kalshi calcs
Is the OddsAssist Kalshi fee calculator free?
Yes. It runs without an account. The site sells a Prediction Markets Pro subscription for its odds data, but the price is not shown on the calculator pages.
Does OddsAssist have a Polymarket fee calculator?
Yes. It models taker fees of 0.05% to 2.5% and a 1.25% maker rebate, and states that the fees apply to the U.S. version of Polymarket.
How does the OddsAssist Kalshi calculator handle maker vs taker orders?
Both the fee and payout calculators have an Order Type dropdown with Taker and Maker. The fee output changes with the selection, but the page does not print the underlying rates.
Does OddsAssist pull live Kalshi prices?
No. You enter the contract price in cents by hand.
Trackers find the edge. Calculators size it. Alerts time it.
When it is time to execute, the free Kairos terminal trades Kalshi, Polymarket and Predict.fun from one book.