Smarter Trades - Free Betfair Trading Tools

Q: Are these tools guaranteed to make me a profit?

No. The calculators are designed to help you understand stakes, liability, expected value and bankroll management. They cannot predict results and do not guarantee that you will make money.

Free calculators for exchange bettors – no login, no cost.

Lay Liability Calculator (Featured Tool)

See exactly how much you stand to lose when laying a selection.

Lay side · Betfair / exchange

Laying a selection means you win if it loses, but your liability can be many times your stake. Use this calculator before you place a lay bet so you know exactly how much is at risk if the favourite or runner you oppose goes on to win.

How it works

How the calculation works

Core formula: Liability = (Lay Odds − 1) × Lay Stake

Worked example: Lay stake £10 at odds 4.5 with 2% commission.

Liability = (4.5 − 1) × £10 = £35.00.
Win profit (if selection loses) = £10 × (1 − 0.02) = £9.80.

For Betfair & exchange traders

Dutching, lay liability, hedging & staking – done properly.

Use these free tools to size your stakes, balance your books and stress-test your edge before you place a trade. Everything runs in your browser – we never see your data.

Included: Dutching · Lay · Fix-a-Bet · Hedge · EV · Kelly · Matched betting · Acca · Odds converter
No signup: Just type & calculate
Privacy: No tracking of inputs

What’s inside?

Nine quick calculators to help you trade smarter on Betfair, Matchbook, Smarkets and other exchanges.

Dutching stakes — Equalised profit
Lay liability — Risk per lay
Fix-a-Bet — Repair a mistaken lay
Back/lay hedge — Green up
Expected value (EV) — Edge per bet
Kelly staking — Bankroll
Matched betting — Qualify & free bets
Acca calculator — Combine multiple legs
Odds converter — Formats & implied probability

About these tools

These free Betfair trading calculators are designed for exchange bettors who want to size stakes accurately and understand their edge before placing a trade. All calculations run locally in your browser – there is no login, no tracking of your inputs and no third-party API usage.

Use the dutching calculator to spread stake across multiple outcomes.
Use the lay liability calculator to control your risk before laying.
Use the Fix-a-Bet calculator to repair a mistaken lay or partial match.
Use the back/lay hedge calculator to green up a position at new odds.
Use the expected value calculator to sanity-check whether a price is value.
Use the Kelly staking calculator to size stakes based on your edge.
Use the matched betting calculator to balance qualifying and free bet offers.
Use the acca calculator to combine multiple legs into one price.
Use the odds converter to translate between fractional, decimal, American and implied probability.

How to use these calculators

Pick the tool that matches the decision you’re trying to make (dutching, lay, hedge, EV, staking or matched betting).
Enter your odds, stakes and estimated win chances using decimal odds (e.g. 3.5 instead of 5/2).
Review the profit, liability and expected value numbers shown in the result box.
Use the output to adjust stakes or skip bets that don’t offer a clear edge.

The numbers are a guide, not a promise. Results in live markets will always vary and past performance is no guarantee of future returns.

Frequently asked questions

Do I need a Betfair account to use these tools?

No. These calculators work with decimal odds from any betting exchange or bookmaker. Just enter the odds and stakes you are using and the tools will calculate the figures for you.

Do you store my bets or track what I enter?

No. All calculations are performed in your browser only. We do not ask for an email address, do not require a login and do not store any of the values you type into the calculators.

Are these tools guaranteed to make me a profit?

Absolutely not. The calculators are designed to help you understand stakes, liability, expected value and bankroll management. They cannot predict results and do not guarantee that you will make money.

Can I use the tools for horse racing, football and other sports?

Yes. As long as your market uses decimal odds, you can use the dutching, lay, Fix-a-Bet, hedge, EV, Kelly, matched betting, acca and odds converter calculators on any sport, including horse racing, greyhounds, football, tennis and more.

Do I have to pay to use the calculators?

No. The tools on this page are free to use. In future there may be additional guides or resources linked from this site that are paid products, but the calculators themselves are free.

Guides & Resources

Learn the trading maths behind the tools

Use these deep-dive guides to sharpen your approach before you open a calculator.