A generated 24-hour movers snapshot plus three calculators for the math you actually use in prediction markets: convert Polymarket odds into probabilities, check whether a trade is +EV, and size risk. No signup.
Static snapshot of active prediction markets with the largest 24-hour odds moves, current price, volume, and liquidity.
Inputs: Public Polymarket API snapshot.
Outputs: Market question, odds, 24h change, volume, liquidity.
Open movers watchlist →
Convert Polymarket prices to implied probability — and your probability estimate to a fair share price. The first thing to do before any trade.
Inputs: Market price, or your probability %.
Outputs: Implied probability, fair price.
Open calculator →
Plug in market price, your true probability, and bet size. See EV in dollars and percent, with green/red verdicts so you know whether to take the trade.
Inputs: Market price, your probability %, bet amount.
Outputs: EV in $ and %, take/skip verdict.
Open calculator →
A free Kelly criterion calculator for prediction-market bet sizing. Includes full Kelly plus 1/2 and 1/4 Kelly so the output is useful even when your edge estimate is uncertain.
Inputs: Bankroll, your edge %, decimal odds.
Outputs: Optimal bet size in $ and % of bankroll.
Open calculator →
The usual workflow is: a market catches your eye in the biggest movers watchlist → use the probability calculator to compare its price to your view → use the EV calculator to check the edge → use the Kelly calculator to size risk. Watchlist first, trade only after the thesis is clear.
The Polymarket odds converter is the fastest way to translate a YES price into implied probability. A 62¢ contract means the market is pricing roughly a 62% chance. If your estimate is 70%, the same tool converts that view back into a fair 70¢ price before you check EV or sizing.
Polymarket prices are direct probabilities, which makes the math cleaner than traditional sportsbooks but also more unforgiving. There's no vig hiding your edge — but there's also no margin for sloppy sizing. These calculators handle the formulas so you can focus on the question that actually matters: is your probability estimate better than the crowd's?
What is the Polymarket odds converter?
It is the implied probability calculator in this toolkit: enter a Polymarket YES price like 0.62 and it returns 62% implied probability, or enter your own probability and it returns a fair price.
Which tool should I open first?
Start with the biggest movers watchlist if you need ideas, then use the odds converter, EV calculator, and Kelly calculator to check probability, edge, and risk size.
For more, read our Polymarket trading strategies guide, the risk management guide, or the portfolio management guide.