What are prediction markets?

Prediction markets let you buy and sell shares on the outcome of real-world events (elections, tariffs, crypto prices). Prices reflect collective probability estimates. If you believe the market underprices an outcome, you can profit by buying YES shares.

How does Polymarket work?

Polymarket is a decentralized prediction market on Polygon. Users buy YES or NO shares that pay $1 if the outcome occurs. No platform fees. Popular for politics, economics, and crypto. Subject to regulatory scrutiny in some jurisdictions.

What is the Kelly criterion for bet sizing?

The Kelly criterion calculates the optimal fraction of your bankroll to bet based on your edge. Formula: f* = (bp - q) / b, where b is odds, p is your win probability, q = 1-p. Full Kelly maximizes growth but has high variance; many use half-Kelly.

What is expected value in prediction markets?

EV = (Your Win Prob × Profit if Win) - (Your Loss Prob × Bet Amount). Positive EV means the bet is profitable long-term if your probability estimate is accurate. Only bet when EV > 0.

Can I bet on China policy or tariff outcomes?

Yes. Polymarket and other platforms offer markets on tariffs, trade policy, and geopolitical events. As reported by Rest of World, Polymarket has faced regulatory questions. Always check platform availability in your jurisdiction.

How do platform fees affect my returns?

Polymarket, Kalshi, and Metaculus charge 0% fees. PredictIt charges 5% on profits. Fees reduce your effective payout and should be factored into expected value calculations.

5 more

HOTPolymarket, KalshiFebruary 2026🌍 GLOBALEconomy & Markets

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Prediction Markets Boom — Traders Bet Millions Against Tariffs and Won

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Prediction markets like Polymarket and Kalshi have exploded in popularity, with traders wagering millions on political, economic, and sports outcomes. Using the Kelly criterion and expected value analysis, sophisticated bettors are finding profitable opportunities. This calculator helps you analyze any prediction market bet.

Concept Fundamentals

$500M+

Market Volume

Monthly trades

2M+

Polymarket Users

Active traders

15-30%

Avg Return

Top traders

Optimal

Kelly Criterion

Bet sizing method

Ready to run the numbers?

Why: Prediction markets aggregate crowd wisdom on real-world events. Prices reflect implied probabilities. If you believe the market underprices an outcome, you can profit by buying YES shares. As Wired reports, traders bet against tariffs and policy outcomes. As Rest of World covers, Polymarket has faced regulatory questions. Use expected value and Kelly criterion to size bets.

How: The calculator evaluates your bet by comparing your personal probability estimate to the market probability. It computes expected value (EV), optimal Kelly bet size, edge percentage, and potential profit after platform fees. Polymarket, Kalshi, and Metaculus charge 0% fees; PredictIt charges 5% on profits.

Your expected value for any prediction market betOptimal Kelly criterion bet sizing based on edge

Methodology

📊Polymarket Coverage

Rest of World reporting on Polymarket regulatory landscape

📈Wired Tariff Betting

Wired reports on traders betting against tariffs

🎯Kelly Criterion

Optimal bet sizing formula for long-term growth

Sources:Rest of WorldWired

Run the calculator when you are ready.

Calculate Expected ValueAnalyze prediction market bets with Kelly criterion

Bet Details

Bet Amount ($)

Market Probability (%)

Your Probability (%)

Platform

Shares/Contracts

Probability Wheel

YES

POSITIVE EDGE

$150

Potential Payout

Edge: 15.0%

pred_market_analysis

CALCULATED

Expected Value

$37.50

Potential Profit

$150.00

Kelly Optimal

$250.00

Edge %

15.0%

Prediction Market Analysis

+$37.50

EV • Edge 15.0% • Kelly $250

numbervibe.com/calculators/trending/prediction-market-betting-calculator

Probability Comparison

Payout Breakdown

YES vs NO

Bet Sizing

For educational and informational purposes only. Verify with a qualified professional.

Prediction markets aggregate crowd wisdom on real-world events. Prices reflect implied probabilities. If you believe the market underprices an outcome, you can profit by buying YES shares. As Wired reports, traders bet against tariffs and policy outcomes. As Rest of World covers, Polymarket has faced regulatory questions. Use expected value and Kelly criterion to size bets.

Key Takeaways

• Edge = Your probability minus market probability. Positive edge = value bet.
• Expected Value = (Win Prob × Profit) - (Loss Prob × Stake). Only bet when EV > 0.
• Kelly Criterion maximizes long-term growth. Use half-Kelly for lower variance.
• Platform fees matter: Polymarket/Kalshi/Metaculus 0%, PredictIt 5% on profits.

Did You Know?

📊Polymarket has processed billions in volume on prediction marketsSource: Rest of World

📈Wired reports traders bet against tariffs on prediction platformsSource: Wired

🌐Kalshi is CFTC-regulated for US usersSource: Kalshi

📉PredictIt charges 5% on profits, reducing effective returnsSource: PredictIt

How Prediction Markets Work

Prediction markets let you buy YES or NO shares on events. Prices reflect collective probability. If you buy YES at 40¢ and the event resolves YES, you receive $1 per share. Your profit = $1 - $0.40 = $0.60 per share.

Expected Value Formula

EV = (p × Profit) - ((1-p) × Stake). Where p = your estimated win probability.

Kelly Criterion

Kelly % = (bp - q) / b. b = odds (1/marketProb - 1), p = your win prob, q = 1-p. Full Kelly maximizes growth but has high variance; half-Kelly is recommended.

Platform Comparison

Platform	Fees	Regulation
Polymarket	0%	Decentralized
Kalshi	0%	CFTC
Metaculus	0%	Forecasting
PredictIt	5%	CFTC

Tariff & China Policy Betting

As reported by Wired and Rest of World, prediction markets offer markets on tariffs, trade policy, and geopolitical events. Polymarket has faced regulatory scrutiny. Always verify platform availability in your jurisdiction.

Disclaimer: Prediction markets involve financial risk. Not legal in all jurisdictions. For educational purposes only. Past performance does not guarantee future results.

Prediction Markets Boom — Traders Bet Millions Against Tariffs and Won

Bet Details

Probability Wheel

Probability Comparison

Payout Breakdown

YES vs NO

Bet Sizing

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Key Takeaways

Did You Know?

How Prediction Markets Work

Expected Value Formula

Kelly Criterion

Platform Comparison

Tariff & China Policy Betting

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