Odds Converter
Convert between American, Decimal, Fractional odds and implied probability instantly.
Open Tool →Arbitrage Calculator
Find guaranteed-profit arbitrage opportunities across 2-way and 3-way markets.
Open Tool →Parlay Calculator
Calculate parlay odds, payouts, and run Monte Carlo simulations to reveal true house edge.
Open Tool →Expected Value Calculator
Compare the expected value and ROI of multiple bets side by side.
Open Tool →Kelly Criterion Calculator
Calculate optimal bet sizing using the Kelly Criterion with bankroll drawdown simulation.
Open Tool →Hold & Vig Calculator
Calculate the hold percentage and vigorish across sportsbooks to find the best value.
Open Tool →Cash Out vs Hedge Calculator
Compare the sportsbook cash out offer against manually hedging to find which gives more value.
Open Tool →Bonus Rollover Calculator
Calculate whether a sportsbook bonus is actually worth taking after factoring in rollover requirements.
Open Tool →Why Sharp Bettors Use Calculators
The difference between recreational bettors and professionals comes down to one thing: math. Recreational bettors go with their gut, chase parlays, and accept whatever odds the book gives them. Sharps run the numbers before every bet — and these are the exact tools they use to do it.
Finding Value Before You Bet
Every sportsbook bakes a margin into their odds. On a standard -110/-110 line, the house takes roughly 4.5% off the top. The Hold & Vig Calculator shows you exactly how much each book is charging, so you can shop for the lowest juice. Over a full season of bets, the difference between a 4.5% hold and a 2.5% hold is hundreds or thousands of dollars staying in your pocket instead of the book's.
The Odds Converter removes the guesswork when comparing lines across books that use different formats. When one book shows -115 and another shows 1.87 decimal, you need to compare apples to apples instantly — not fumble with mental math and miss the window.
Sizing Your Bets Correctly
Most bettors lose not because they pick the wrong side, but because they bet the wrong amount. The Kelly Criterion Calculator tells you exactly what percentage of your bankroll to wager based on your edge. Bet too much and one bad streak wipes you out. Bet too little and you leave money on the table. Kelly finds the sweet spot — and the built-in simulation shows you what different bet sizes actually look like over hundreds of wagers.
Before you even place a bet, run it through the Expected Value Calculator. If the EV is negative, no amount of luck will save you over time. If it's positive, you have an edge worth exploiting. The batch mode lets you compare your entire slate at once and focus your bankroll on the highest-ROI spots.
Advanced Strategies
The Arbitrage Calculator finds guaranteed-profit opportunities where two books disagree on the odds enough that you can bet both sides and win regardless. True arbs are rare, but when they appear, this tool tells you exactly how to split your stakes for maximum profit.
When your bet is in a winning position and the book offers a cash out, the Cash Out vs Hedge Calculator tells you whether to take it or manually hedge at another book for a better deal. Sportsbooks price their cash outs 5-15% below fair value — the calculator shows you exactly how much you'd save by hedging yourself.
Got a bonus offer? Run it through the Bonus Rollover Calculator before you accept. A $500 bonus with a 10x rollover costs you roughly $227 in expected vig to clear at standard juice. Some bonuses are genuine value; others are traps disguised as generosity. The calculator tells you which is which — and simulates 10,000 clearing attempts to show you the bust probability.
Parlays: Know What You Are Paying
Sportsbooks push parlays hard because the house edge compounds with every leg. A 3-leg parlay at -110 each carries roughly 13% house edge compared to 4.5% on straight bets. The Parlay Calculator shows the true cost and runs a Monte Carlo simulation so you can see, in hard numbers, how parlays perform over thousands of trials. If you still want to play them, at least go in with your eyes open.
All Tools Are Free and Private
Every calculator on this page runs entirely in your browser. We don't collect your inputs, don't require an account, and don't limit how many times you can use them. Bookmark this page and come back before every bet. The math is the same math the sharps use — now you have access to it too.
