Matched Betting Calculator
Enter your bookmaker and exchange details below to calculate the correct lay stake, liability, and expected profit/loss for both outcomes.
What is a bet and lay calculator?
A bet and lay calculator is a simple tool used in matched betting to balance two opposite bets: a back bet at a bookmaker and a lay bet at a betting exchange. The goal is to reduce risk and create predictable outcomes, regardless of whether the selection wins or loses.
Instead of guessing your lay stake, this calculator computes it using the odds and exchange commission you enter. It then shows what happens in each scenario so you can understand your true position before placing any bet.
How this calculator works
1) Qualifying bet mode
Use qualifying mode when you are placing a normal cash stake at the bookmaker. In this case, your stake is returned by the bookmaker if the bet wins. The calculator uses the standard formula:
Lay Stake = (Back Odds × Back Stake) / (Lay Odds − Commission)
The result typically gives a small, controlled loss called a qualifying loss, which is often the cost of unlocking a bookmaker promotion.
2) Free bet (stake not returned) mode
Use free bet mode when the bonus stake is not returned as cash winnings. Here, only the profit part matters on the bookmaker side, so the formula changes to:
Lay Stake = ((Back Odds − 1) × Back Stake) / (Lay Odds − Commission)
This mode is commonly used after completing a qualifying offer and receiving a free bet token.
What each output means
- Lay Stake (exact): the precise theoretical lay amount.
- Lay Stake (rounded): practical amount to place (typically 2 decimal places).
- Lay Liability: money the exchange requires if your selection wins.
- Profit if selection wins: combined result of bookmaker and exchange when the team/horse wins.
- Profit if selection loses: combined result when the selection does not win.
Step-by-step example
Suppose you place a £10 qualifying back bet at odds of 3.5, and the lay odds are 3.6 with 5% exchange commission:
- Back odds: 3.5
- Back stake: £10
- Lay odds: 3.6
- Commission: 5%
The calculator returns a lay stake around £9.86 and a liability around £25.64. After rounding, your two possible outcomes will be close together (usually a small qualifying loss either way).
Common mistakes to avoid
- Using the wrong mode (qualifying vs free bet stake not returned).
- Forgetting to set the correct exchange commission rate.
- Placing a rounded lay stake but expecting exact theoretical profits.
- Mixing up back odds and lay odds fields.
- Ignoring minimum stake rules at bookmaker or exchange.
Practical tips for better accuracy
Check market liquidity
If there is low liquidity on the exchange, your lay bet might only partially match. Always confirm that the full lay stake is matched before the event starts.
Record every bet
Maintain a simple spreadsheet with date, event, odds, stake, lay stake, liability, and final outcome. This helps you measure true long-term returns and quickly spot input errors.
Round consistently
Most exchanges let you enter two decimal places for stake. Because of that, your real-world profits differ slightly from exact formulas. This calculator shows both exact and rounded figures so your plan is realistic.
Responsible gambling reminder
Matched betting still involves real-money transactions and operational risk. Odds can move, markets can suspend, and mistakes can happen. Only use funds you can afford to lock up temporarily, and never chase losses from unrelated betting activity.
This page is for educational and planning purposes only, not financial advice.