Thirty-four free betting calculators covering the maths that sits under every wager: expected value, implied probability, staking, settlement and the margin your bookmaker charges. Each tool runs in your browser, prices in decimal odds by default, and shows the working alongside the result.
Nothing here needs an account. Pick a calculator, enter your figures, read the answer.
Core Betting Tools
Value, margin and staking – the sums that decide whether a price is worth taking before anything else gets a look.
- Expected Value (EV) Calculator – test whether a price holds positive expected value against your own probability estimate.
- Implied Probability Calculator – convert any price into the win rate it needs to break even.
- No-Vig / Fair Odds Calculator – strip the bookmaker margin from a market and see the fair price for each outcome.
- Hold / Vig Calculator – measure the margin built into a market, so you can compare bookmakers on the same match.
- Kelly Criterion Calculator – size your stake from your edge and your bankroll, with fractional Kelly options.
- Bet Payout Calculator – total payout and profit for any stake, in decimal, fractional or American odds.
- Arbitrage Betting Calculator – split a stake across two prices so the return is the same whichever side wins.
Odds Converters
Seven converters covering every pairing of decimal, fractional and American odds, each with the implied probability behind the price.
- Odds Converter (All Formats) – enter a price in any format and get the other two.
- Decimal to American Odds – decimal price in, moneyline out.
- American to Decimal Odds – moneyline in, decimal price out.
- Decimal to Fractional Odds – decimal price to the nearest bookmaker fraction.
- Fractional to Decimal Odds – fractions such as 11/8 into decimal, ready for accumulators.
- American to Fractional Odds – moneyline to a fraction in lowest terms.
- Fractional to American Odds – fraction to moneyline, with a note on where rounding bites.
Parlays, Hedging & Free Bets
Combined bets, plus the tools that manage the other side of them: locking a profit, converting a free bet or pricing the gap between two lines.
- Parlay Calculator – combined odds, return and profit for a multiple at decimal prices.
- Round Robin Calculator – every double from your legs, the all-win profit and what survives a loser.
- Free Bet Conversion Calculator – the lay stake and liability that turn a free bet into withdrawable cash.
- Matched Betting Calculator – back and lay figures for qualifying bets, with the small loss either way.
- Middle Bet Calculator – profit and breakeven hit rate when two lines leave a gap the result can land in.
- Hedge Betting Calculator – the lay stake that locks a profit on a position you already hold.
Specialist Tools
Model-driven and market-specific calculators for the questions the standard tools leave open.
- Poisson Calculator (Football) – goal-count probabilities, over/under splits and correct score odds from expected goals.
- Betting Exchange Back & Lay Calculator – profit, liability and effective odds after commission.
- Prediction Markets Calculator – contract prices in cents translated into implied probability, decimal odds and expected value.
- US Gambling Winnings Tax Calculator – federal withholding on winnings and what actually lands in your account.
UK Multiples & Each-Way
Full-cover bets settled line by line, from the four bets in a Trixie to the 247 in a Goliath, plus each-way settlement with your own place terms.
- Trixie Bet Calculator – three selections, four bets: outlay and return at any winner count.
- Patent Bet Calculator – three selections, seven bets, singles included.
- Yankee Bet Calculator – four selections, 11 bets across doubles, trebles and the four-fold.
- Lucky 15 Calculator – four selections, 15 bets with singles.
- Lucky 31 Calculator – five selections, 31 bets.
- Lucky 63 Calculator – six selections, 63 bets.
- Heinz Bet Calculator – six selections, 57 bets from the doubles upward.
- Super Heinz Calculator – seven selections, 120 bets.
- Goliath Bet Calculator – eight selections, 247 bets, settled in one pass.
- Each-Way Calculator – win and place returns from your odds, stake and place terms.
Every tool on this page works on numbers you already have. Finding the numbers worth having is the harder job – that is what the Gecko Edge platform does, with properly modelled xG and EV analysis across 130+ leagues. Try it free at app.geckoedge.ai. No card required.
Betting Calculator FAQs
Are these betting calculators free?
Yes. All 34 calculators are free, run in your browser and work without an account. Enter your figures and the result appears as you type.
Which odds format do the calculators use?
Decimal odds are the default throughout, because they keep the maths easiest to follow. The payout calculator accepts fractional and American prices as well, and the seven converters translate between all three formats.
Which calculator should I use for an accumulator?
The parlay calculator prices a straight accumulator where every leg must win. If you want cover when a leg loses, the full-cover tools – Trixie through Goliath – settle every combination and show the return at each number of winners.
Do the calculators tell me what to bet on?
No. They do the arithmetic on figures you supply: value, stakes, returns and margins. What you back stays your decision. For match-level analysis behind those numbers, that is the job of the Gecko Edge platform.