Odds comparison
Kalshi vs Polymarket odds comparison tools
Tools that line up the same event across Kalshi, Polymarket and other venues so you can see the best price before you trade.
Checked September 8, 2026 · every price read off the live site
Every odds comparison tool
4 reviewed · alphabetical-
Kairos Cross-venue trading terminal: Kalshi, Polymarket and Predict.fun in one order book, with sub-second data and advanced order types.
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Oddpool The most direct Kalshi vs Polymarket comparison: divergence tracking with fee context, plus a real data API underneath.
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Prediction Hunt Live odds from six venues in one view and one API call.
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Prediction Market Odds Comparison (Apify) A pay-per-row dataset of the same question priced on Kalshi, Polymarket and PredictIt, with the gap and whether it clears both books.
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PredScope A free Polymarket odds tracker with a Polymarket versus Kalshi fact sheet and a no-auth JSON API that refreshes every 10 minutes.
Built a odds comparison tool that is missing here? Submit it. One condition: a page on your site that links to this directory.
| Tool | Venues | Pricing | Type |
|---|---|---|---|
| Oddpool | Kalshi, Polymarket, Opinion | Free tier: $0, 1,000 API requests per month. | web app |
| Prediction Hunt | Kalshi, Polymarket, Polymarket US, ProphetX, Predict.fun, PredictIt, Opinion, Crypto.com, OG.com | Site free. | web app |
| Prediction Market Odds Comparison (Apify) | Kalshi, Polymarket, PredictIt | $5.00 per 1,000 matched cross-venue pairs on Apify. | API |
| PredScope | Polymarket, Kalshi | Free. | web app |
How these tools work
Odds comparison tools put the same event's price from several prediction market venues on one screen, so you buy where it is cheapest and see where venues disagree. Prediction Hunt covers the most venues, nine on its homepage and seven in its API. Oddpool goes deepest on Kalshi versus Polymarket with fee and spread context. DefiRate's Fed page does it for one event class across six venues.
The gap between comparing and trading is the whole category. Every tool here shows prices; the order still goes in on each venue's own site, so speed of refresh and honesty about fees matter more than venue count.
Two of the tools are Apify Actors that return a dataset rather than a page, which suits analysts who want the comparison in a sheet on a schedule.
How to choose
- Venue coverage that matches where you have funded accounts. A ninth venue you cannot trade adds nothing.
- Live versus snapshot: Prediction Hunt and Oddpool stream; DefiRate updates hourly; PredScope every 10 minutes; the Apify Actors give a snapshot per run.
- Whether the same event is truly matched. Check resolution source and date on both venues before treating a price difference as an edge.
- API availability and free quota if you plan to pull prices into your own tooling: Prediction Hunt gives 1,000 free calls a month, Oddpool 1,000, PredScope unlimited with no key but Polymarket-only data.
- Business model. Comparison sites that carry venue sign-up offers earn on referrals; that does not make the prices wrong, but read the ordering with that in mind.
Questions about odds comparison tools
What is the best site to compare Kalshi and Polymarket odds?
Prediction Hunt for breadth across nine venues at no cost, Oddpool for Kalshi versus Polymarket divergence with fee context on its free tier, and DefiRate for Fed decision odds across six venues.
Is there a free prediction market odds comparison API?
Yes. Prediction Hunt's free tier gives 1,000 requests per month across seven venues with an X-API-Key header, and PredScope offers a keyless JSON feed sourced from Polymarket.
Why do Kalshi and Polymarket show different odds for the same event?
Different fee structures, different user bases and jurisdictions, different liquidity, and sometimes different resolution criteria. DefiRate and Oddpool both note that fees and bid-ask spreads explain part of any gap.
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.