Net edge

The number

House edge tells you what a game costs you per bet. Bonuses and rakeback give some of that back. Neither figure alone tells you what you are actually paying — the two have to be combined:

Why this reverses most comparisons

Take a slot with a 3.5% house edge at a casino returning half of it. Net edge lands at 1.75%. Now take a plain 1% game somewhere that offers nothing at all. No bonus, no rakeback, no rewards page.

The second one is better by a wide margin — you pay 1% instead of 1.75%, so the generous-looking casino costs you three quarters more per bet.

This is not a trick example. It is the normal situation, because a casino funds its rewards out of its own margin. The money in the rewards programme came from the edge in the first place. A high edge with generous giveback and a low edge with nothing can easily land on opposite sides of where intuition puts them.

Compare two offers

What the returned figure has to include

The comparison only works if the "returned" number is what you will genuinely receive, which is rarely the headline. Things that quietly reduce it:

Wagering requirements. A bonus at 20× or 40× turnover is not worth its face value — you have to bet it through many times over, paying the edge each pass. Worked through, a large matched bonus routinely returns a fraction of what its number suggests.

Game contribution rates. Rewards often pay less on live tables or certain titles than on slots. If your game contributes at half rate, halve the figure you put in the box.

Expiry and claim windows. A reward you have to be online to collect, within a window, is worth less than one credited automatically — because sometimes you will miss it.

Vague terms. Rules about bet sizing during wagering, or clauses about "abuse" left undefined, are conditions under which a payout can be refused. That is not a small risk to price in; it is the difference between the reward existing and not existing.

Why casinos do not simply cut the edge

If the net edge is what matters, the obvious move would be to skip the machinery and offer a lower edge outright. Same net cost, none of the complexity.

They do not, and the reason is that the complexity is doing a job. A bonus creates a reason to come back, a deadline to meet, a balance that feels earned. A lower house edge creates none of those. The hoops are the product.

Which is also why the arithmetic is worth doing yourself: it is the one thing that cuts through every version of the presentation.

Where Duel sits

Duel makes this argument itself and does not run bonuses at all — it returns a share of the house edge on every bet instead, credited immediately with no wagering. Whether that produces a better net edge than a rival still depends on both numbers, so put them in the calculator rather than taking anyone's word for it, this site included.

Related: what a rakeback percentage is worth and how house edge is derived from the rules.