Calculate the stakes for greening up or Back/Lay arbing

Do you want to trade out on a betting exchange or arb Back and Lay prices, but don't know what stake to use to ensure a level profit whatever happens?

Look no further than our free online calculator on this page that does all the hard work for you. It breaks down the profit figures into the P&Ls from the Back and Lay bets and the commission payable on the winning bet (for cross-market trades/arbs) or on the net market profit from both bets (for same-market trades/arbs), so that you can see exactly how the Net Profit is obtained.

(Chrome users should select "Click to enable Adobe Flash Player" above to activate the calculator.)

Back/Lay betting calculator instructions

The calculator is very intuitive and simple to use, but we've provided some brief instructions below just in case. Don't hesitate to if you have any queries.


Enter both prices (decimal, fraction or US format).
The Back Price must be higher than the Lay Price to ensure a guaranteed profit.
The calculator automatically converts fractional or US prices to exchange-friendly decimals.


Enter one stake value.
Enter Lay Stake for trades on a price rise or if there is a constraint (liquidity etc) on your Lay bet in a Back/Lay arb.
Enter Back Stake for trades on a price fall or if there is a constraint (liquidity, max stake limit etc) on your Back bet in a Back/Lay arb.
Enter Total Stake if you want to specify how much you'll spend on a Back/Lay arb or on a cross-market trade.
If you enter two stake values, the first value will be cancelled (reset to 0.00).

Back and Lay selection on same exchange

Select for same-market bets (placing both bets on the same market on the same exchanghe).
Clear for cross-market bets (different exchanges or exchange + bookmaker).
This setting determines whether commmission is applied to each indiviual bet (cross-market) or to the market profit (same-market).


Enter the applicable commission rate(s) on your bets.
The default Commission for Lay bets is 5.00%.


Press Calculate to view the stake(s) required to win the same Net Profit whatever the result.
Back Bet Profit and Lay Bet Profit show the profits from each of the two bets.
Commission Paid shows the commission deducted by the betting exchange.
Yield is obtained by dividing the Net Profit by the Total Stake and indicates the profitability of the trade or arb.

See our trading and betting instructions for more detailed instructions.

Useful exchange with the same prices and liquidity as Betfair, but not available in the UK or the US.