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 · Hedge · EV · Kelly · Matched betting
No signup Just type & calculate
Privacy No tracking of inputs
Always gamble responsibly. These tools are for information only and do not guarantee profit.
Free exchange calculators built for clarity
These free Betfair trading calculators are designed for exchange bettors who want to size stakes accurately
and understand their edge before placing a trade. Use the dutching calculator to spread your
stake across multiple horses or football outcomes, the lay liability calculator to control
your risk, the back/lay hedge calculator to green up an existing position at new odds, the
expected value (EV) calculator to check whether a price is value, the
Kelly staking calculator to manage your bankroll over the long term, and the
matched betting calculator to balance qualifying and free-bet offers. All calculations run
locally in your browser – there is no login, no tracking of your inputs and no third-party API usage.
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.
Dutching Calculator
Split your total stake across multiple runners for equal profit.
Multi-runner markets
Dutching lets you back multiple outcomes in the same market and aim for roughly the same profit whichever
selection wins. Traders often use it in horse racing, correct-score and other markets where more than one
runner looks overpriced and they want to spread their risk.
Lay Liability Calculator
See 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.
Back/Lay Hedge Calculator
Green up a position by adding a second bet at new odds.
Hedge trades
When odds move in your favour you can lock in a profit by placing the opposite bet at the new price.
This hedge calculator shows the stake needed on the second bet to level your position so that you end up
with a similar profit whichever way the market settles.
Expected Value (EV) Calculator
Work out your edge based on your estimated chance of winning.
Find +EV bets
Expected value (EV) tells you whether a price is in your favour over the long run. If your estimated
win chance is higher than the market’s implied probability, the bet is theoretically value. Use this
calculator to sanity-check your edge before staking real money.
Kelly Staking Calculator
Size your stake as a fraction of your bankroll based on your edge.
Bankroll management
Kelly staking links your edge to your stake size. When you believe you have a strong edge it suggests
staking more; when your edge is small it recommends reducing stakes. Many traders use half-Kelly or smaller
fractions to control drawdowns and avoid aggressive swings in bankroll.
Matched Betting Calculator
Balance qualifying bets and free bets with the right lay stake.
Qualifiers & SNR free bets
Use this matched betting calculator to keep qualifying losses small and lock in profit from stake-not-returned free
bets. Enter the back odds from the bookmaker, the lay odds on the exchange and your commission rate to see the lay
stake, liability and profit for each outcome.
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, hedge, EV, Kelly and matched betting
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.
