How To Use The OddsMonkey Calculator

how to use the oddsmonkey calculator

A matched betting calculator is a vital component of all matched betting sites and OddsMonkey is no exception. In this article we are going to take a look at the OddsMonkey calculator and explain how some of it’s features can be used to assist your matched betting exploits.

Three Bet Types

Normal - This mode is used for most qualifying bets and completing bonus rollover requirements. By using this function, you can reduce qualifying losses on qualifying bets with ease. Close matches at low odds are best here. Just remember to consider any minimum odds requirements and market restrictions when looking for a suitable bet.

You will begin by entering the back stake for your bookmaker bet. This is followed by the decimal odds of that bet and a commission percentage, if necessary. Next, enter your lay odds and exchange commission. 

Once all of the data is entered correctly, you will be shown some results beneath the calculator. Here you will be advised the ideal lay stake to place on the betting exchange and what the liability will be. Liability is the amount of money required in your account to cover the bet. Finally a profit/loss figure will be shown in green or red respectively, with a full breakdown at the bottom.

Free Bet (SNR) - Most free bets are credited on a stake not returned (SNR) basis. All this means is that if the free bet wins, the value of the free bet token will not be included in the returns. This mode is used for generating a cash profit from said free bets and doing so is fairly easy.

The profit is made because you are not betting with your own money. As a rough guide, most matched bettors look to retain 80% of the free bet value, so a £10 free bet is deemed to be worth £8 in cash for example. Selecting a close match at odds of 5.0 or greater is a good way to achieve this.

Start by entering the value of the free bet in the back stake box. Then type in the back odds and adjust the back commission if required. Finally, enter the lay odds and exchange commission to see the advised lay stake. Once again you will be shown a profit figure and full breakdown of how it is generated.

Free Bet (SR) - In truth, it’s very rare that a bookmaker will give a free bet where the stake is returned. This is the mode for that situation. Getting as close a match as possible will generate the best profit but remember that high odds will require a larger balance in the exchange to cover the bet.

You will begin by entering the back stake for your free bet. This is followed by the decimal odds of that bet and a commission percentage, if necessary. Next, enter your lay odds and exchange commission. Once the information is entered, you will be shown a profit figure and full breakdown of how it is generated.

oddsmonkey matched betting calculator


In most cases, operating in Simple Mode will suffice. This includes all ‘bet and get’ style signup offers, plus similar reload offers where a free bet or bonus is given. There may be some instances where Advanced Mode comes into it’s own though. When selecting this feature, you will be given three suggested lay stakes;

  • Underlay - Reduced lay stake for a bigger return at the bookmaker but a smaller payout on the exchange
  • Standard - Regular lay stake for a balanced payout at both bookmaker and exchange
  • Overlay - Larger lay stake for a smaller return at the bookmaker but a larger payout on the exchange
oddsmonkey calculator advanced mode

Beneath the three suggested options is a ‘Custom’ mode slider. This can be adjusted to Underlay or Overlay between preset parameters. You can adjust these parameters manually, should the situation necessitate a larger Underlay or Overlay.

An example of when you may wish to use Underlay is when completing bonus rollover requirements. By doing this you can avoid any qualifying losses if the bookmaker bet wins by accepting a smaller win on the exchange.

An example of when you can use Overlay is when looking to try and make the bet365 4/1 offer risk-free. When using this technique, if the bet loses the bookmaker loss and exchange win will be equal. But if the bet wins, you will make a loss on the qualifying bet but have a risk-free bet that can be used to return a profit.


Every now and then a situation arises when only part of your stake is matched at the exchange. This happens when the lay stake exceeds the market depth on the exchange. This can be avoided by looking for markets with plenty of cash available to lay but most matched bettors run into this problem at some time or another.

oddsmonkey partial lays

It can be pretty frustrating but OddsMonkey has a workaround. You can enter two separate part lay stakes, which the calculator then takes into account before recommending an ideal lay stake for the currently available odds. This allows you to cover the rest of your bet accordingly, which could prevent an unwanted loss.


Strangely, a separate calculator is used for taking advantage of risk-free bet offers. These are offers where a free bet or bonus and sometimes even cashback is given when the qualifying bet loses. An example of which is the Totesport signup offer.

oddsmonkey risk-free calculator

To use this feature, you need to enter the back stake and odds for your bookmaker bet, followed by the lay odds and exchange commission. Then type in the value of the potential refund and the retention percentage. As mentioned earlier, this is usually 80% for a standard SNR free bet.

Once the details are entered, you will be shown an ideal lay stake and the amount of liability required. The full breakdown of each possible outcome will be shown beneath. This feature allows you to achieve the same profit figure, regardless of the outcome of the bet. Close matches at odds of 5.0 or greater will generate the best profit.

EV calculator

The EV calculator is used for calculating the estimated value of casino offers. OddsMonkey's EV calculator is a basic one which works off a standard EV formula and so can only be used accurately for casino offers with no wagering or x1 wagering on the bonus. However, it is a useful tool to have for low-risk casino offers.

oddsmonkey ev calculator

Simply enter the bonus amount, the wagering requirement and the house edge of the casino game you are playing on and the calculator will display the EV of the offer.

If you are looking for a more advanced EV calculator which can accurately determine the EV of casino offers with higher wagering and which it's possible to bust on, Profit Squad provides members with one of the most advanced casino calculators on the market and is seriously worth looking at.


The OddsMonkey calculator has most bases covered and is easy enough to use. The back and lay sections are the same colour as the buttons on Betfair which is great for familiarity. We did find it to be a minor inconvenience to have to switch to a different calculator when looking to profit from risk-free bets. The part lay functionality is good but only allows for two part lays. Other services such as Matched Bets have more calculator modes and allow for unlimited part lays but all in all, most users will find the calculators at OddsMonkey sufficient and they have pretty much all bet types covered throughout their range of calculators.

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