Betting Calculators is a free, privacy-friendly toolkit for sports bettors. Five tools in one: Parlay (combined odds & payout), Odds Converter (Decimal/American/Fractional), Hedge (lock in guaranteed profit), Market Hold (bookmaker margin), and Value/EV (spot value bets). No sign-up, no tracking, works offline. Also available as a browser extension and userscript. Made by CorrectBetting.