Free betting calculators
Sharp betting is a numbers game. These seven calculators — plus a what-if ROI simulator — give you the math layer every serious bettor needs before placing a stake. No sign-up, no email gate, no paywall on results.
The EV Calculator answers the only question that matters: is this bet positive expectation? Enter your stake, the decimal odds on offer, and your true-probability estimate. The formula EV = stake × (odds × probability − 1) does the rest. Positive EV does not guarantee a win — variance rules the short run — but it is the only repeatable edge you can compound over hundreds of bets.
The Parlay Calculator multiplies leg odds to show you the combined price, total payout, and implied probability. Use it to understand the actual cost of stringing legs together before you commit. The Odds Converter translates between decimal, American, fractional, and implied percentage in real time — useful whenever you are comparing prices across books that show different formats.
EV Calculator
Expected Value & ROI
Enter your stake, decimal odds, and true probability estimate. Get expected value in EUR and ROI % instantly.
Find +EV bets →
Parlay Calculator
Combined odds & payout
Add 2–10 legs with decimal odds and a stake. See combined odds, total payout, and the implied probability of hitting every leg.
Calculate parlay payouts →
Odds Converter
Decimal · American · Fractional · Implied
Convert any odds format to the other three instantly. Includes a static reference table for the most common lines.
Convert odds formats →
Kelly Criterion Calculator
Optimal bet sizing
Enter bankroll, odds and win probability. Get the full, half and quarter Kelly stake — including 'no bet' when the edge is negative.
Size your stake →
Devig & No-Vig Calculator
4 methods · Shin, power, additive
Strip the margin from any 2- or 3-way market with four de-vig methods side by side — multiplicative, additive, power and Shin. See the overround and the bias-corrected fair odds.
Remove the vig →
Arbitrage Calculator
Surebet check & stake split
Enter the best odds per outcome across books. See whether an arb exists, the margin, and the exact stake split for an equal payout.
Check for arbs →
Hedging Calculator
Lock an equal result
Enter your open bet and the current odds on the other side. Get the exact hedge stake and the result you lock either way.
Calculate your hedge →
ROI Simulator
What-if backtesting
Simulate how a staking plan would have performed: flat vs Kelly sizing, win rate and odds assumptions, equity curve included.
Run a simulation →