The in-house games at Ossi Ketola’s Duel return, on average, every dollar staked, up to $50,000 in wagers per player each day. Here is a plain-English guide to how the zero-edge offer works, which games it covers and what it means for the people playing.
Almost every casino game comes with a hidden price. At Duel.com, the crypto casino that Finnish founder Ossi Ketola launched in July 2025, that price has been set to zero on the games it builds itself. If you have ever wondered how that works, this guide takes it one question at a time.
First, what is a house edge?
Every casino game pays out slightly less than the true odds. The gap between the two is the house edge, and it is how a casino earns its money. The gambling mathematics reference Wizard of Odds puts it in a single line: “The house edge is defined as the ratio of the average loss to the initial bet.”
A familiar example makes it concrete. On a single-zero roulette wheel the edge is 2.70%, according to Wizard of Odds, so a player staking $100 can expect to lose $2.70 of it on average, bet after bet. Add a second zero, as American wheels do, and the edge climbs to 5.26%. Slot machines range from 2% to 15% on the same reference table, and keno takes between 25% and 29%. Over millions of bets, even a small edge adds up.
Which games are zero edge at Duel?
The offer covers Duel Originals, the range Ketola’s company builds in-house. It includes dice, blackjack, plinko, crash, mines and keno: quick, simple games with clear rules and fast results. Keno is a useful illustration of the gap. On the Wizard of Odds table it is one of the costliest games in a traditional casino; in Duel’s own range it sits at zero alongside everything else.
So how does the edge get to zero?
Two things happen at the same moment. “For now, originals have a base 0.1% edge,” Duel’s zero-edge FAQ explains. That tenth of a percent is then handed straight back as each bet is placed: “When you are within your zero edge allowance, all of your bets receive a 0.1% instant rakeback, therefore making your net edge zero.”
In money terms, the numbers are tiny and they cancel exactly. On a $100 bet, the base edge represents 10 cents, and 10 cents comes back the moment the bet is placed. Scale that up and the balance holds: across a full day’s allowance of $50,000, the base edge comes to $50, and the instant rakeback returns the same $50.
There is nothing to claim and nothing to unlock. The rakeback is applied bet by bet, automatically.
Is there a limit?
Yes. Each player can wager up to $50,000 a day at zero edge. Once that allowance is used, “the 0.1% instant rakeback on bets stops until your limit resets the next day,” and a scaling house edge applies to further play. The following day, the full allowance is back.
It helps to know what counts. The allowance measures the total amount staked, not the amount deposited, so every bet placed adds to the running figure. Someone playing $100 a round would reach the cap after 500 bets; someone playing $10 a round would have 5,000 bets before it applied.
For a sense of scale, the same $50,000 staked on a single-zero roulette wheel would carry an expected cost of $1,350 at the 2.70% Wizard of Odds figure, and $2,630 on a double-zero wheel. Within its allowance, a
Duel Originals player carries an expected cost of nothing.
What’s the catch?
A cautious reader will suspect one: a casino that charges nothing must be hiding the cost or heading for trouble.
In fact the limits are printed, not hidden. The first is the daily cap, and Duel states the reason plainly: “If we allowed people to bet millions at zero edge,” the FAQ says, “we would almost certainly lose millions.” The cap is what keeps the offer affordable, every day. The second is that the zero-edge promise stops at the Originals; the wider catalogue is priced conventionally, as the next section explains.
Nor is a capped zero-edge bet new. Wizard of Odds lists the craps “odds” bet at 0.00%, and Wikipedia’s entry on the game notes that “Most casinos have a limit on how large the odds bet can be in relation to the line bet”. Duel applies the same principle to a whole range of games, with the ceiling set per player per day.
What about the rest of the site?
Games outside the Originals, including the slots and other third-party titles, carry their own edge, and Duel shares part of it back with players as rakeback. Either way, the house edge of every game is shown on that game’s own page, so a player can see the price before placing a bet. That matters most for exactly those titles: with slots spanning 2% to 15% on the Wizard of Odds table, a posted figure turns a hidden cost into a number anyone can compare.
So what does that mean for players?
Put simply, the odds are fair. “When the house edge is zero,” the FAQ says, “the odds of you winning or the casino winning are exactly even.” Individual sessions still rise and fall, as any game of chance does, but the built-in cost of playing over time is gone. Measured against the Wizard of Odds definition, the average loss on the initial bet is zero.
Why do it at all?
For Ossi Ketola, it comes down to what gambling should be. Removing the edge, Ketola says, offers “gambling in its purest possible form”. The whole mechanism, from the 0.1% base edge to the daily reset, is set out on Duel’s own website for anyone to read.
