Betting calculators
Free Betting Calculators
Use these free betting calculators to understand odds, implied probability, bookmaker margin, no-vig fair odds, expected value, arbitrage stakes, dutching stakes, hedge bets, free bets, matched betting, back/lay positions, lay liability, Kelly staking, accumulators, each-way returns, dead heats, extra places and Rule 4 deductions.
Most useful betting calculators
These are the core Betting Maths calculators. They are designed to explain the numbers behind betting, not to provide betting tips or predictions.
Odds Converter
Convert decimal, fractional and American odds, and calculate implied probability.
Open calculator →Overround Calculator
Calculate book percentage, overround and bookmaker margin in a betting market.
Open calculator →No-Vig Fair Odds Calculator
Remove margin from a simple two-outcome market and estimate fair probabilities and fair odds.
Open calculator →Expected Value Calculator
Estimate expected value and expected ROI from stake, odds and your probability estimate.
Open calculator →Arbitrage Calculator
Check whether odds create an underround and calculate the stake split across all outcomes.
Open calculator →Dutching Calculator
Split a total stake across two or more selections for a balanced return.
Open calculator →Hedge Bet Calculator
Calculate back-first and lay-first hedge stakes, lay liability, commission and profit or loss.
Open calculator →Back/Lay Calculator
Calculate lay stake, lay liability and profit across standard back bets and free bet examples.
Open calculator →Free Bet Calculator
Calculate lay stake, lay liability, profit and conversion rate for free bet offers.
Open calculator →Matched Betting Calculator
Estimate qualifying loss, free bet profit, lay stakes and overall matched betting result.
Open calculator →Lay Liability Calculator
Calculate lay liability, exchange commission and profit or loss from a lay bet.
Open calculator →Kelly Criterion Calculator
Estimate stake size from bankroll, odds, your estimated probability and fractional Kelly.
Open calculator →Accumulator Calculator
Multiply odds across multiple selections and calculate acca returns, profit and implied probability.
Open calculator →Each-Way Calculator
Calculate total stake, place odds, win profit, place-only result and losing outcome.
Open calculator →Dead Heat Calculator
Estimate adjusted returns, profit or loss and equivalent odds after a dead heat.
Open calculator →Each-Way Extra Places Calculator
Compare standard each-way results with enhanced extra places offers.
Open calculator →Rule 4 Calculator
Estimate horse racing Rule 4 deductions, adjusted profit and adjusted return.
Open calculator →Which betting calculator do I need?
If you are not sure which calculator to use, this table gives a quick guide.
| What you want to calculate | Best calculator | What it shows |
|---|---|---|
| Convert odds or calculate implied probability | Odds Converter | Decimal, fractional, American odds and implied chance. |
| Check bookmaker margin in a market | Overround Calculator | Book percentage, overround and market margin. |
| Remove bookmaker margin from a two-outcome market | No-Vig Fair Odds Calculator | Implied probabilities, no-vig fair probabilities and fair odds. |
| Estimate expected value from stake, odds and estimated probability | Expected Value Calculator | Profit if win, expected value, expected ROI and an EV result message. |
| Check whether odds create an arbitrage | Arbitrage Calculator | Underround, stake split, equal return and estimated profit. |
| Split stakes across multiple selections | Dutching Calculator | Stake per selection, return and equalised profit or loss. |
| Hedge an existing betting position | Hedge Bet Calculator | Back-first or lay-first hedge stakes and outcomes. |
| Back first, then lay on an exchange | Back/Lay Calculator | Lay stake, lay liability, commission and balanced result. |
| Convert a free bet into profit | Free Bet Calculator | Lay stake, liability, conversion rate and free bet profit. |
| Estimate a matched betting offer | Matched Betting Calculator | Qualifying result, free bet result and estimated overall profit. |
| Understand the risk on a lay bet | Lay Liability Calculator | Lay liability, gross win, commission and result if the selection wins or loses. |
| Estimate stake size from an edge | Kelly Criterion Calculator | Full Kelly, fractional Kelly, edge and suggested stake. |
| Work out accumulator returns | Accumulator Calculator | Combined odds, return, profit and implied probability. |
| Calculate each-way returns | Each-Way Calculator | Total stake, place odds, win result, place-only result and loss. |
| Calculate adjusted returns after a dead heat | Dead Heat Calculator | Winning stake portion, losing stake portion, adjusted return and equivalent odds. |
| Compare standard places with extra places | Each-Way Extra Places Calculator | Standard result, extra places result and the difference. |
| Estimate horse racing Rule 4 deductions | Rule 4 Calculator | Original profit, deduction amount, adjusted profit and adjusted return. |
Odds, probability and market margin calculators
These calculators help explain the price of a bet, the probability implied by the odds, the expected value of a position, and the margin built into a market.
Staking, offers and returns calculators
These calculators help work out possible returns, deductions, offer value and stake sizing from common betting situations.
Exchange and hedging calculators
These calculators help with back bets, lay bets, liability, commission and hedging.