Free Betting Calculators

Matched betting

Back stake: the amount placed with the bookmaker. Enter decimal odds for the same selection at the bookmaker and exchange.

Commission: your exchange’s rate. Liability: the balance needed to cover your lay bet.

Staking modes: Standard balances both outcomes equally. Underlay aims for £0 loss if the bookmaker back bet wins. Overlay aims for £0 loss if the exchange lay bet wins.

2Up early payout

Pre-match setup: balances your back and lay bets so your qualifying loss is minimal.

2-0 Up lock-in: when your team goes 2 goals ahead, the bookmaker pays out in full. Enter the current in-play exchange back odds to calculate the exact stake to back the team, balancing your estimated profit across results.

Expected value

EV = stake × (offered odds ÷ fair odds − 1).

Your fair odds are an estimate. EV is the modelled average across repeated bets, not this bet’s payout. Fees and offer conditions are excluded.

Kelly stake model

A mathematical stake based on your estimated win probability and chosen Kelly fraction. A zero stake means no positive Kelly allocation.

Arbitrage & Dutching

Splits a budget or locks leg 1 across 2-way or 3-way mutually exclusive outcomes covering every result.

Enable rounding (nearest £1 or £5) to place natural-looking stakes and protect accounts from bookmaker restrictions.

No-Vig / Fair Odds

Sharp bookmakers and exchanges include a profit margin (vig/overround). This calculator strips the overround to find the true mathematical probability and fair odds.

Use the "Send to +EV" or "Send to Kelly" buttons to quickly evaluate whether a recreational bookmaker's price offers positive expected value.

Odds converter

Decimal: 2.50 · Fractional: 3/2 · American: +150 · Probability: 40%.

Implied probability is the break-even win rate in the price, including bookmaker margin.