Casino offers are a great way to build EV and contribute a decent proportion of many matched bettors long term profit. There are a wide variety of casino offers and the majority of these will involve using slots. Important factors to consider when picking a slot for any particular offer is the Return to Player (RTP) percentage and the variance of the slot.

Before considering factors such as RTP and variance, it is useful for us to understand how slots work. The large number of slots on offer does not make this an easy task, but after a few offers, you should start to get the hang of how different slots operate which is what we’ll be looking at in this matched betting guide.

Ready to start Matched Betting?Join OddsMonkey Today

Symbols and paylines explained

Almost all slots have 5 columns, 3 or 4 rows and a number of paylines operating from left to right (and sometimes right to left). As you spin the slot, each column/row will display different symbols. The value of these symbols differs but most slots have a number of low paying symbols (commonly 10, J, Q, K and A) and a number of premium symbols. If a certain number of the same symbols appear on a payline, you will get a return on your bet. Some slots will also have wild symbols, which can act as any other symbol to create a winning line. The returned amount depends on the number of symbols on the payline, with the biggest payouts coming from a full line of the same symbol.

Most slots also have bonus rounds, which is often where you can expect to hit the biggest wins. Entering a bonus round usually requires a number of ‘scatter’ symbols to appear on the reels. Bonus rounds differ greatly from slot to slot so it would be impossible to cover them all here, but generally, they fit into a couple of categories. One type is the ‘picking’ bonus round where you may have the option to pick a number of chests or similar to be awarded cash. Another type is a free spin bonus round where you get a number of free spins, often with multipliers, special wilds and other features.

As matched bettors we must remember that most of this is for show and to draw punters in, each slot has a fixed RTP and we cannot control it; each spin is independent of the other. The winnings from most bonus rounds are predetermined before the feature even starts!

Staking on slots

The most important thing to consider when you have chosen your slot is the stake size. This will be dependent on the type of offer you are doing. If it is a low-risk casino offer you will generally want to stake small with your own cash. If you are doing an Advanced Casino Offer your stakes will often be much bigger, which is all explained within our training guides.

For most slots, you can set your overall stake easily by clicking an increase/decrease button. However, some slots also have the option to set your stake per line or have the ability to increase/decrease the ‘bet level’. Most of this is for show and gives the punter the illusion that they are somehow having an effect on the outcome. The most important thing for us is the overall stake, which should always be displayed somewhere. It is important that the overall stake falls within the strategy as well as within the terms and conditions of the offer.

In the examples below, the overall stake is displayed below the spin button. In the first one, we have the bet level set as 1 and the coin value as 0.02 (0.02 per line, this is a 20-line slot). In the second, we have the bet level set as 2 but the coin value as 0.01 (0.01 per line twice). The overall stake of £0.40 is the same for both.

online slots


You will find that many slots also have an ‘Autoplay’ feature. If we click on this, it allows us to set a number of spins and a max loss value. The slot will then spin for the set number of spins and only stop once these have finished or you have hit your max loss value. As matched bettors this can be useful as it sometimes allows us to do multiple offers at once with several slots open all set to autoplay, greatly increasing our EV per hour.

Below we will go through some categories, which, broadly speaking, most slots will fall into.

9-10 line slots

With a 9-10-line slot, it is not uncommon to see wins of 100x or 200x your stake for a 5 of a kind line. Sometimes you may also have one or two wilds on screen which may mean you hit 2 or 3 similar lines in the same spin. Popular examples of 9-10 slots include: Dead or Alive 2, Book of Dead, Book of Ra Deluxe, Fishin’ Frenzy, Starburst and Pimped.

9-line slots

20-25 line slots

These are the most common slots and you will normally see minimum spin values of £0.20 or £0.25 a spin. If you have been used to playing 10 line slots and suddenly you are getting wins where, at a glance, it appears that no symbols have lined up; it will be because there are more active paylines than you are used to. Expect wins to still be quite significant if you hit 5 of a kind lines on the high paying symbols, but not as big as if you were playing a 10 line slot, with most big wins instead, coming from bonus or scatter features. Popular examples include: Guns n Roses, TED, Rainbow Riches, Street Magic, Gonzo’s Quest and Jack and the Beanstalk.

20-line slots

40-60 line slots

This is the level at which individual 5 of a kind lines are no longer as exciting; wins per line are smaller the more lines you have, so you generally need a lot more of the same symbol on screen to produce 5 or 10+ line wins. This doesn’t mean these slots are any worse; all are programmed to perform according to their RTP% regardless of their number of lines. However, you may find that these slots typically have a lower variance, particularly when compared to 10 line slots. This means that you may win small and often as opposed to hitting big and rare wins. Examples include: Wild Wolf, It’s Magic, Icy Wilds, Batman & The Batgirl Bonanza, Jungle Giants and Fat Rabbit.

40 line slots

243+ line slots

Assuming a 5 x 3 grid of rows and columns, these are the slots in which every possible combination of left to right is a payline (3 x 3 x 3 x 3 x 3 = 243), meaning if you have any one symbol appearing anywhere at least once in each column, you will hit a win. Slots with larger grid, 5 x 4 for example, may have 1024 lines (4 x 4 x 4 x 4 x 4) or more.  Wins are smaller per line but often these are the slots that produce the most astounding wins, with a full screen of the same symbol possible. Examples include: Immortal Romance, Epic Ape, Buffalo Blitz, Vikings, Raging Rex and Twin Spin.

Megaways slots

Megaways slots are becoming more popular with many of the classic slots being transformed into Megaways. The easiest way to explain Megaways is by looking at the reels. These slots pay and play across set reels with a varied number of symbols per reel. They have a random number of symbols shown on any reel for every spin, instead of the classic static rows of symbols. With each spin, the reels change so that the number of ‘Megaways’ changes and can pay up to 117,649 ways! Popular examples include Bonanza, Extra Chili, Diamond Mine, Genie Jackpots Megaways, Fishin’ Frenzy Megaways and Vikings Unleashed Megaways.

megaways slots


When doing casino offers, our slot choice can be important. RTP and variance are important and their effect on the EV of an offer can be seen when using the Profit Squad casino calculator. However, it is also important for us to understand how slots work so that we do not make mistakes, for example, setting our desired stake per line instead of total bet. We need to be sure our total bet falls within the strategy and the terms of the offer. Additionally, for matched bettors, the autoplay feature can be very handy to increase our EV per hour, so we should try to look for slots that contain this feature.

Ready to start Matched Betting?Join OddsMonkey Today