Download the appBy Outlier · Updated
About the Prediction Markets Converter
A prediction-market contract can pay $1 if its outcome happens and $0 if it does not. This tool converts the purchase price into betting odds and estimates costs and profit using the fees you enter.
How to use this calculator
- Choose whether to start with a contract price in cents or betting odds.
- Enter the price for the side you want to buy.
- Enter the number of contracts and your total estimated fee per contract.
- Compare the matching odds, cash needed, winning profit, and break-even win chance after fees.
Formula and definitions
- Win chance implied by the price = c ÷ 100. Decimal odds before fees = 100 ÷ c.
- Total cost = number of contracts × (c + fee in cents) ÷ 100.
- Profit if the contracts win = number of contracts × $1 − total cost.
- Break-even win chance after fees = (c + fee in cents) ÷ 100.
- c
- The purchase price of one contract in cents.
- Contract
- One unit that settles at $1 or $0 in this model.
- Gross odds
- The odds from the purchase price before fees.
- Break-even chance
- The win chance needed to cover the purchase price and entered fees.
Worked example
- A 65-cent contract implies a 65% win chance before fees.
- That is about 1.5385 decimal, -186 American, or 7/13 fractional odds.
- Buying 100 contracts costs $65 before fees.
- If they settle at $1 each, you get $100 back and make $35 profit.
How to read your result
Gross odds use the price alone. Fees raise your cost and the win chance needed to break even.
The opposite-side cents value is a comparison number. It is not a live price you can trade at.
Assumptions and limitations
- This model assumes each contract settles at $1 or $0. Check the market’s resolution and void rules.
- Use a price you can buy at for your chosen quantity. The last trade or midpoint may not be available.
- You supply the fees. The tool does not load platform fee rules or account for price changes as you buy.
Common mistake to avoid
A last trade at 65 cents does not mean you can buy the number of contracts you want at that price.
Put your result to work
Try a related calculator, or read our sports betting strategy guides to learn more.
- Odds Converter — Odds formats & payout
- Implied Probability Calculator — Break-even win chance
- Expected Value Calculator — Average profit or loss
Prediction Markets FAQs
What odds is a 50-cent contract?
Before fees, 50 cents means a 50% implied win chance. That equals 2.00 decimal, +100 American, or 1/1 fractional odds.
Are Kalshi or Polymarket fees included?
Only the fees you enter are included. Check the platform’s current fees for that market, then enter the total estimated cost per contract.
How results are calculated
Results use the formulas and assumptions above. Money is rounded to cents. Odds and percentages are rounded to make them easier to read.
The calculator uses the odds and win chances you enter. It does not load live odds.