Welcome to our Tools section

Here you can find our Calculators. - designed to complement your Prediction Market trading.
Please note these are for illustration purposes only and should not be taken as Financial advice

you should check your platform fees are reflected accurately.

Prediction Market Toolkit

Prediction Market Toolkit

BetBreakingNews calculator tools — pricing, book % analysis, value, hedging, arbitrage, scenario planning, and event-count markets across prediction platforms and sportsbooks.

Start simple, then go deeper

This tool is ordered for discovery. New users can begin with one price or one market, then move into hedge sizing, cross-venue execution, scenario planning, and count-market pricing.

Level 1 — Price & Value

Check a single contract after fees, convert it into break-even probability and bookmaker odds, then compare it to your own probability estimate.

Level 1 — Book % / Dutching

Work a full market with 2 to 10 selections. See overround, fair probabilities, fair odds, and equal-payout or fixed-stake splits.

Level 2 — Risk & Execution

Size opposite-side hedges and check whether two venues create guaranteed profit after fees.

Level 3 — Scenario & Counts

Map portfolio P&L across linked binary events, or price exact-count / over-under markets using an expected event rate.

1. Price & Value
2. Book % / Dutching
3. Risk & Execution
4. Scenario Matrix
5. Count Markets
Odds & Fees
Expected Value
Free Bet EV
Multi-leg EV

Odds & Fees

Use this when you want the real entry cost of one YES or NO contract after venue fees.

Platform fee guide

Kalshi
7% taker fee on trade notional risk term price × (1-price), charged on entry. In this tool it is treated as an upfront trading fee, not a profit-share fee.
Polymarket
2% on profit in this model. Treated as a P&L fee on winning profit only.
PredictIt
10% on profit in this model. Treated as a P&L fee on winning profit only.
Ruckus
2% on profit in this model. Treated as a P&L fee on winning profit only.

This toolkit uses a simple execution model: Kalshi = upfront trading fee; others = fee on winning profit. It does not model maker rebates, spread capture, partial fills, exchange commission tiers, or settlement-time exceptions.

Book % / Overround / Dutching

For multi-runner markets. Enter 2 to 10 selections as decimal odds, American odds, or raw probabilities.

Hedging
Arbitrage: PM vs PM
Arbitrage: PM vs Sportsbook

Hedging

Size the opposite side of an existing position. Use this to flatten risk or shape the payout range.

3-Market Scenario Matrix

Enter up to three linked binary positions. The table shows portfolio P&L under all 8 outcome combinations.

Count Market Model

Price event-count contracts such as “exactly 3 resignations”, “2 or fewer rate cuts”, or “over 4 indictments”. First estimate the average number of events in the period, then choose the contract you want priced.

This is the long-run average count for the period, not the most likely single outcome.

How to use this

Average count (lambda)
Your estimate of how many times the event happens on average over the period. If you have past data, use the helper to turn those previous counts into an average automatically.
Target k
The contract threshold. Example: for “exactly 2”, set k = 2. For “over 2”, also set k = 2.
Range a to b
Use this when the market is a band, such as 2 to 4 inclusive.

Good rule of thumb: if you observed counts of 1, 2, 0, 3, 2 across five comparable periods, the average is 1.6. That is a sensible starting lambda.

Examples:
• “Exactly 2 rate cuts this year” → Exact, k = 2
• “At most 2 resignations this month” → Under, k = 2
• “More than 4 indictments” → Over, k = 4
• “Between 2 and 4 leadership changes” → Range, a = 2, b = 4