At a Glance
Rating Breakdown
Performance Overview
Scores out of 5, based on our editorial analysis
About Manifold Markets
Manifold Markets is the prediction market for people who want to test their forecasting ability without risking real money. The platform uses a play currency called "mana" -- you get free mana when you sign up, earn more by making accurate predictions, and can spend mana to create new markets on any topic you want. There is no way to convert mana directly to cash (a regulatory requirement that keeps Manifold from being classified as a gambling or financial platform). You can, however, donate mana to charity partners, converting your prediction skill into real charitable impact. This structure is not a compromise -- it is a deliberate design choice rooted in the Effective Altruism community where many of Manifold\'s founders and core users come from. The surprising finding about Manifold -- and the reason forecasting researchers take it seriously -- is that play-money markets are more accurate than you would expect. Academic studies comparing Manifold\'s calibration to real-money platforms like Polymarket and PredictIt show that Manifold\'s aggregate predictions are within 3-5 percentage points of real-money markets on most questions. The reason: Manifold\'s core user base is disproportionately composed of serious forecasters -- rationalists, data scientists, policy analysts, and EA community members who care about their track record and calibration score even without financial incentives. When Philip Tetlock\'s research on superforecasters showed that some people are consistently better predictors than the crowd, Manifold became the platform where those people practice. Anyone can create a market on Manifold, which is both its greatest strength and its limitation. There are over 100,000 markets on topics ranging from geopolitics to AI timelines to whether a specific podcast will release a new episode this week. The quality varies enormously: some markets have dozens of knowledgeable traders and tight calibration, while others are inside jokes with three participants and meaningless prices. The community self-moderates through reputation -- each user has a public track record showing their prediction accuracy, profit/loss history, and calibration curve. Traders with strong track records carry more implicit weight in market pricing than anonymous newcomers.
Key Features
Create Markets on Anything
Unlike regulated platforms that must have every market approved, Manifold lets any user create a market on any topic. Want to predict whether a specific open-source project will reach 10,000 GitHub stars by year-end? Whether your city council will approve a zoning change? Whether a friend will finish their marathon under 4 hours? Create the market in 30 seconds and share the link. This flexibility makes Manifold useful for personal, organizational, and niche predictions that no commercial platform would list.
Calibration Tracking
Manifold tracks every prediction you make and charts your calibration -- when you say something has a 70% chance of happening, it should happen about 70% of the time. Your calibration curve is public on your profile. This feature turns prediction from a casual opinion exercise into a rigorous skill-building practice. Serious forecasters use Manifold specifically for this feedback loop, which does not exist on platforms where you only see profit/loss.
Community and Reputation System
Every user has a public profile showing their prediction track record, total mana profit/loss, markets created, and comments. Good forecasters build reputations over time. The platform surface top predictors on leaderboards, and their market participation signals credibility. This reputation layer replaces the financial incentive of real-money platforms -- instead of money motivating accuracy, status and track record do.
Charity Donation Conversion
Mana cannot be converted to cash, but it can be donated to Manifold's charity partners at a rate that converts play money into real charitable impact. This means your prediction skill has a tangible outcome even without financial stakes. The charity feature is particularly popular in the EA community, where members compete to earn mana through accurate forecasting and then direct it to effective charities.
Open Source and Transparent
Manifold's codebase is fully open source on GitHub. Anyone can audit the market mechanics, the automated market maker algorithm (a modified LMSR), the resolution process, and the mana distribution system. This level of transparency is unmatched by any commercial prediction market. If you disagree with how something works, you can literally read the code and file a pull request.
Multiple Market Types
Beyond simple Yes/No markets, Manifold supports numeric range markets (predict a specific number), multiple choice markets (pick from several options), free response markets (submit your own answer), and even stock-like markets for ongoing entities. This flexibility allows questions that binary prediction markets cannot handle well, like "How many seats will Democrats win in the Senate?"
How It Works
Sign Up (Free, No ID Required)
Create an account with just an email address or Google/Apple sign-in. No SSN, no identity verification, no KYC. You receive starting mana immediately. The entire process takes under a minute.
Explore or Create Markets
Browse existing markets by category (politics, technology, AI, science, culture, personal) or search for specific topics. If you cannot find what you want, create your own market in 30 seconds -- define the question, set the resolution criteria, and choose a close date.
Make Predictions
Buy Yes or No shares using mana. The price reflects the crowd's estimated probability. If you think the crowd is wrong, you make money by betting against them and being right. Your calibration score updates with every resolved market, showing whether you are overconfident, underconfident, or well-calibrated.
Build Your Track Record
Over time, your profile shows your prediction accuracy across hundreds of markets. Use this data to identify your forecasting strengths and weaknesses. Share your calibration curve with employers, research teams, or forecasting competitions. Donate earned mana to charity if you want tangible impact from your skill.
What They Do
- Play-Money Prediction Markets
- Custom Market Creation
- Calibration Tracking
- Community Forecasting
- Charity Donation Conversion
- Forecasting Tournaments
Debt Types They Take On
- Binary Markets
- Numeric Range Markets
- Multiple Choice Markets
- Free Response Markets
- Stock-Like Markets
Fee & Cost Structure
Regulatory & Trust
Review Summary
Notable Case Studies
AI Lab Using Manifold for Internal Forecasting
An AI research lab set up private Manifold markets for internal predictions: "Will we hit benchmark X by Q3?", "Will the paper be accepted at NeurIPS?", "Will the compute budget increase next fiscal year?" Researchers traded on these markets using mana, and the aggregate prices became the lab's unofficial probability estimates for planning.
Superforecaster Training Ground
A participant in IARPA's Good Judgment Project (Philip Tetlock's superforecasting research program) used Manifold to maintain her forecasting skills between tournament seasons. She created 200+ predictions per month across politics, science, and technology, using the calibration tracking to identify areas where she was consistently overconfident.
Journalism Newsroom Forecasting
A political journalism team created Manifold markets on the outcomes of stories they were covering: election results, policy decisions, court rulings. Reporters traded on these markets, and the editors used market prices as a reality check against their own narrative assumptions.
Pros & Cons
Pros
- Completely free -- no money at risk, no fees, no deposits
- Anyone can create a market on any topic in 30 seconds
- Calibration tracking helps you improve as a forecaster over time
- Strong community of serious forecasters (rationalists, data scientists, EA members)
- Open source codebase -- fully transparent and auditable
- Available worldwide with no geographic or regulatory restrictions
Cons
- Play money means no real financial stakes -- predictions may be less serious
- Market quality varies wildly because anyone can create markets (many are low-quality or inside jokes)
- Smaller community than Polymarket -- thin markets on some questions
- Mana has no cash value, so there is no direct financial reward for being right
- Less accurate than real-money markets on some questions (though the gap is smaller than expected)
- Can feel like a game rather than a serious forecasting tool, which puts off some users
User Reviews (13)
Fun hobby
I treat it like a brain exercise. Make a few predictions every morning with coffee. Nice way to think about the world probabilistically. Not taking it too seriously though.
Good for learning
I used Manifold for 6 months before putting real money on Kalshi. Learned a lot about how prediction markets work, how to think in probabilities, and how to spot mispricings. Great training wheels.
Wish there was real money
I like the platform but mana doesn't pay my bills. Would love a real-money version of this with the same market creation flexibility. I know that's a regulatory nightmare but a guy can dream.
Surprisingly accurate
I compared Manifold prices to Polymarket on overlapping questions for three months. Manifold was within 3-4 percentage points on average. For free play money, that's remarkable. The community is self-selecting for people who actually care about accuracy which compensates for the lack of financial incentives.
good
It's free and kinda fun. I predict stuff about TV shows mostly.
EA community loves this
If you're in the EA or rationalist community this is essential. We use it for everything from AI timelines to org strategy to personal predictions. The fact that it's free and open source makes it perfect for our use case.
The AI timelines markets are unmatched
Nobody else has prediction markets on specific AI capabilities and timelines. Manifold has hundreds of them, traded by people who actually work in AI. The aggregate forecasts are more useful than any analyst report I've read. This is where the field's real expectations live.
Best forecasting training tool
I've been on Manifold for a year and my calibration score went from 0.78 to 0.90. That matters to me because I do forecasting professionally. The platform is like a gym for prediction skill. Free, community-driven, and the calibration tracking is the killer feature.
Great for niche questions
Try finding a market on "will the next Python release include pattern matching improvements" on Kalshi. You can't. On Manifold someone already made it. That's the value -- you can predict on anything, no matter how niche.
Market creator resolved wrong and nothing happened
Created a bet on a market about whether a bill would pass committee. It did pass. The creator resolved it as NO because they "didn't see the news." I flagged it and it took 2 WEEKS for a mod to fix it. My mana was locked the whole time. The resolution system needs serious work if they want anyone to take this seriously.
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- Prediction market contracts involve risk of loss. You can lose your entire stake on any contract. Past accuracy of market predictions does not guarantee future results.
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