How we score slots

Four inputs, each turned into a number from 0 to 10, then weighted and added up:

Each factor is rounded to one decimal place, multiplied by its weight, and the total is rounded to one decimal again. That's the Spin Score.

Why these weights? RTP is the one number that tells you what a game costs to play over time, so it gets the most. The free spins round is where most modern slots put their best ideas, and it's what people actually choose a game for, so it gets 30%. Max win and the base game matter, but less. They split the rest.

RTP is scored on a straight line. 94% or below scores 1. 97% or above scores 10. Everything in between is proportional, so every 0.1 percentage point of RTP is worth 0.3 on the scale, or 0.12 on the final Spin Score. A 96% game scores 7.0 for RTP; a 96.5% game scores 8.5.

The range looks narrow. It is, on purpose. Of our 105 slots, 93 publish a top RTP between 96% and 97%. A scale from 0% to 100% would give almost all of them the same score and hide real differences. Only two slots reach 97% or more (Blood Suckers at 98% and Wild Swarm at 97.03%), and three sit at the 94% floor.

We use the highest setting the studio publishes. That's the fairest way to compare games, and it's also a ceiling you may not get. Studios sell lower versions and casinos choose: 65 of our 105 slots list at least one lower setting, and 24 list one below 90%. Every page tells you to check the game's info screen, and we mean it. Our RTP guide explains how.

Max wins range from 300x (Finn and the Swirly Spin) to 300,000x (Tombstone RIP) in our data. A straight line would let a handful of extreme games flatten everything else. So max win uses a log scale: 500x or less scores 2, 50,000x or more scores 10, and each tenfold step in between adds 4 points. 5,000x scores 6. The median slot in our data has a 10,000x max win, which gets 7.2 on this scale.

The top is capped at 50,000x because past that the number stops meaning anything to a player. A max win is the most the maths allows on one spin or round, and it's extremely rare. Nolimit City gives the odds for Mental's 66,666x as 1 in 18 million. Twenty-five of our slots reach the cap, and Tombstone RIP gets the same 10 as a 50,000x game.

Not every studio means the same thing by max win. Push Gaming publishes a "highest observed win", the largest win it has recorded, rather than a cap. NetEnt's stats box sometimes disagrees with its own feature text: Dead or Alive 2 shows 1,600x in the box and 100,000x in the Train Heist description. Where that happens, the record says which figure we used and why, and the page says so too.

Two of the four inputs are judgement calls, scored 0 to 10 by the editors from the studio's own description of the game. Each comes with a one-line reason in the record. The rubric:

Free spins round (30%). 9 to 10: a feature people seek the game out for, with real escalation, such as multipliers that grow, retriggers, or several bonus choices. 7 to 8: a strong, clear free spins round. 5 to 6: standard free spins with one twist. 3 to 4: thin. 0 to 2: no meaningful bonus.

Base game (15%). 8 to 10: constant features between bonuses, like tumbles, random wilds or modifiers. 5 to 7: some. 2 to 4: mostly dead spins until the bonus.

We try to use the whole scale. In practice, 33 slots score 7 for their bonus and 25 score 8. Only the three Money Train games score 10, for the Money Cart. Starburst gets a 2 because its only feature is a wild respin. On the base game side, Reactoonz and Reactoonz 2 score 9, and Dead or Alive scores the lowest, a 2, for long stretches where nothing happens.

Where a studio doesn't describe its bonus, we don't guess upward. Queen of Riches Megaways gets a plain 5 because the free spins aren't documented.

Razor Returns, our top slot: 0.4 x 8.6 + 0.15 x 10 + 0.3 x 9 + 0.15 x 7 = 3.44 + 1.5 + 2.7 + 1.05 = 8.69, shown as 8.7.

Blood Suckers has the best RTP we've found and still only scores 6.4, because its features are thin and its 900x max win is small. Pirots is the opposite. Good features, a decent max win, and the lowest score on the site, because ELK publishes a 94% RTP and that costs it 7.5 points of RTP score against a 96.5% game (3 points on the final score). The weighting does what it's meant to: a slot can't charm its way past a poor return.

Every number starts on the studio's own game page: pragmaticplay.com, netent.com, playngo.com, hacksawgaming.com, nolimitcity.com, pushgaming.com, bigtimegaming.com, relax-gaming.com, redtiger.com and elk-studios.com, plus the official data sheets some studios link. All checked in November 2026.

Studio pages often leave gaps. Play'n GO's pages list no RTP, volatility or max win at all. Relax Gaming publishes bets and max win but not the headline RTP. When that happens we use the game's official rules or a reputable aggregator, Bigwinboard or SlotCatalog, and the record names which source gave which figure. For Big Time Gaming we also use playin.com, Evolution's official studio site. Across our 105 records, 71 cite Bigwinboard for at least one figure, 25 cite SlotCatalog, 7 cite playin.com, and 10 rely on the studio alone.

Volatility is recorded in five bands, low to very high. When a studio uses a 0 to 10 scale, as NetEnt does, we map below 4 to low, 4 to 5.4 to medium, 5.5 to 6.9 to medium-high, 7 to 8.4 to high, and 8.5 or more to very high. Nolimit City's "Insane" and "Extreme" labels count as very high.

A record missing RTP or max win can't be scored, so it isn't ranked. Right now that's one game, Big Time Gaming's Kingmaker, because no source we trust publishes its max win. We'd rather leave a game out than make up a number.

Every list sorts by Spin Score, highest first, and breaks ties on the higher RTP. Two lists sort by something else on purpose: the highest RTP list sorts by RTP and the biggest max win list by max win, both with the Spin Score as tie-break.

Then a cap, so no single studio takes over a page. Provider pages show that studio's top 10, with no cap. Slot type pages, like Megaways slots, show up to 12 games, three per studio at most. The "slots like it" block on a single-slot guide shows up to six, two per studio. The five rankings allow three per studio. The cap costs Razor Shark a place on the best online slots list: it scores 8.4, but three Push Gaming games score higher.

Volatility. High volatility isn't better or worse than low. It's a preference about how wins are spread out, and the right answer depends on your budget and your patience. So it's shown on every card and used as a filter, never added to the score. Our volatility guide covers what it means in practice.

Popularity. How many people play a game, how often it's streamed, how famous it is: none of it enters the score. Studio claims about being the most played anything are claims, not inputs. That's why Starburst sits near the bottom.

Commission. No studio or casino can pay for a score or a position, and nothing about any commission arrangement goes into the program. The buttons on our cards lead to free demos and our own game pages. How the site makes money is on the affiliate disclosure page, and the rules writers follow are in our editorial standards.

We also don't score bonus buys, bet ranges or graphics. Bonus buys are noted on the card where they exist, and we usually tell you to skip them.