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Start Polymarket tools: what they do, what they cost, where they stop
Last checked 2026-09-08
Start Polymarket is an independent educational site about Polymarket with a tools page of seven calculators. It states it is not affiliated with Polymarket and it carries referral links to the venue.
The set is narrow by design: every tool is Polymarket-only. If you trade one venue and want fee, P&L, EV and Kelly math without sportsbook clutter, that narrowness is the point.
What it does
The Fee Calculator is the differentiated one. It computes Polymarket trading fees by market category, trade size and probability, which matters because Polymarket's fee treatment differs by market type rather than being one flat rate.
The Profit/Loss Calculator returns net profit or loss on a trade including fees, ROI and the math behind it. The EV Calculator compares the market price with your probability estimate. The Position Sizer applies the Kelly Criterion.
The Odds Converter handles Polymarket prices alongside decimal, American, fractional, Hong Kong and Malay formats, more formats than the Kalshi-first sites offer. The Country Availability Checker returns a status for 190+ countries.
- Fee Calculator: fees by market category, trade size and probability
- Profit/Loss Calculator: net result including exact fees and ROI
- EV Calculator and Odds Converter (Polymarket prices, decimal, American, fractional, Hong Kong, Malay and more)
- Position Sizer (Kelly), Referral Calculator (12-month projection), Country Availability Checker (190+ countries)
Pricing
No prices appear on the page and the tools open without an account. The site earns through Polymarket referral links, which it discloses.
Venues and data
Polymarket only. No Kalshi, no cross-venue comparison. Nothing is live; you enter prices.
Where it falls short
A trader on both Kalshi and Polymarket needs a second site for the Kalshi side. There is no arbitrage or hedge calculator here.
The Referral Calculator and Country Checker are onboarding tools for new users rather than trading tools, so two of the seven are not for an active trader.
Who should use it
A Polymarket-only trader who wants category-aware fee math and a Kelly sizer without paying for a suite.
New users get the referral and country tools; active traders get the fee, P&L, EV and Kelly tools. The site is independent, so its fee assumptions come from its own reading of Polymarket's schedule rather than from the venue.
Questions about Start Polymarket tools
Are the Start Polymarket tools free?
Yes. No prices are shown and the tools run without an account. The site carries disclosed Polymarket referral links.
Does Start Polymarket work with Kalshi?
No. All seven tools are Polymarket-only.
Is Start Polymarket affiliated with Polymarket?
No. The site describes itself as an independent educational resource not affiliated with Polymarket.
What does the Start Polymarket fee calculator do?
It computes Polymarket trading fees from market category, trade size and probability, rather than applying one flat rate.
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