Sportsbooks · Exchanges · Kalshi
Every arbitrage is a gap between two prices.
Free calculators and straight guides to find that gap, size both sides and lock in the profit, with the real fees included. No "guaranteed riches", just the math.
3 calculators
Fees verified
Odds: decimal & US
How a gap shows up
Most prices agree. Now and then, one doesn't.
Books update at different speeds. When the best prices on both sides add up to less than 100%, there is an arbitrage. It rarely lasts long.
Simulated prices · for illustration only
| Event | Side A | Side B | Implied | Gap | Status |
|---|
Calculators
Built for the trades that don't go to plan.
Rounding, exchange commission, free bets, Kalshi fees and odds that move halfway through. All handled.
Sportsbooks
Arbitrage Calculator
Split a stake across 2 or 3 outcomes, round it so it looks natural, add commission. Decimal or American odds.
Open calculator → ExchangesBack, Lay & Hedge
Lay stake and liability for normal and free bets, plus a re-hedge tool for when the second leg's odds move.
Open calculator → Prediction marketsKalshi Arbitrage Calculator
Kalshi against a sportsbook or Polymarket, with Kalshi's real fee formula. Size by contracts or by budget.
Open calculator →The method
Three lines of math.
No prediction, no tips. Just prices that disagree enough to cover every outcome.
Odds to probability
Every decimal odd hides an implied probability.
1 / 2.10 = 47.6%Add the best prices
Best odds per outcome, each from a different book. Under 100% is an arbitrage.
47.6% + 48.8% = 96.4%Split the stake
Stake each side by its share, so every outcome pays the same.
$1,000 × 47.6 / 96.4 = $494Straight talk
The numbers nobody puts in the ad.
Start with the real picture, not with your own money.
2–5%
Typical margin per trade
Once both bets are accepted, an arbitrage locks in its margin. Repeated many times a month, small margins become real income.
Limits
Sportsbooks restrict winners
Consistent arbitrage gets accounts limited. Exchanges and prediction markets work differently.
Fees
Fees decide the trade
Commission and Kalshi fees can halve a margin. The full calculators include them.
Guides
Long-form, worked examples, checked numbers.
Tools
Compare tools →
Best Arbitrage Betting Software (2026)
Scanners compared: what to look for, prices and free trials, and our pick for most bettors.
Straight talk
Read the guide →
Is Arbitrage Betting Worth It? The Real Numbers
What a starter and a serious arber make at 2% to 5% margins, what tools cost, and a calculator for your own numbers.
Account longevity
Read the guide →
How to Arbitrage Bet Without Getting Limited
What sportsbooks look for, 10 habits that keep your accounts open for longer, and the venues that don't limit winners.
Prediction markets
Read the guide →
Kalshi Arbitrage: The Complete Guide
Turn contract prices into odds, account for Kalshi's verified fees, and lock in a profit against sportsbooks and Polymarket.
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