How we rank casinos: The Sun Factor for casinos explained

OUR biggest priority when reviewing any online casino is transparency with our readers. Our team of casino experts follows a strict set of criteria when reviewing an online casino, scoring each operator across weighted categories to produce an overall Sun Factor rating out of five. When we assign these scores, our writers draw on hands-on experience with the site and give an honest account of its strengths, weaknesses, and whether it’s worth signing up. In this guide to the Sun Factor, we explain our review process, the conditions every operator must meet, and exactly how our rating system works, including a worked example so you can see how a score is built. It’s also how we choose the best online casinos for you. What’s changed in 2026, and why our ratings are moving Our 2026 re-evaluation. We have rebalanced the Sun Factor and re-scored every casino we rate. This follows the UK Gambling Commission’s 2026 rule changes, including the 10x wagering cap, the £5 and £2 slot stake limits, the ban on mixed-product bonuses, and new mandatory deposit limits and financial-risk checks. In response, we have given more weight to what now matters most to players: how quickly a casino pays out, and how fair its bonus terms are. Payments and payout speed are now our single heaviest category, and bonuses are judged on fairness (wagering, win caps and clarity) rather than headline size. Because every operator has been re-scored under this revised model, some ratings and rankings have moved compared with previous versions. We review our ratings regularly, and this page reflects our most recent full re-evaluation. Here’s what changed and why it matters to your rating: A 10x cap on wagering requirements. Bonuses can no longer bury you in playthrough terms. A “big” bonus with punishing wagering used to look generous; now we score bonuses on how fair the terms are, not how large the headline number is. Stake limits on online slots — a £5 maximum per spin, and £2 for players aged 18 to 24. We check that operators apply these correctly. A ban on mixed-product bonuses that lump casino, bingo, and sports wagering together. Offers have to be cleaner, and we mark down anything that tries to work around it. Mandatory conditions to be met by every operator Before we score anything, an operator has to clear a set of non-negotiable checks. These are pass or fail. A casino that fails any one of them is never reviewed or recommended on our site, regardless of how good the rest of its offering is. 1. UKGC license, valid SSL encryption, and security measures Every operator must be licensed and regulated by the UK Gambling Commission, which allows it to operate legally in the UK and hold to the industry’s safety standards. Every site must use current SSL encryption to protect personal and financial data. We also check whether a site’s games and payouts have been independently audited, a plus, though the licence is the hard requirement. 2. Clear, comprehensive terms and conditions Players deserve to understand exactly what they’re signing up for. We read an operator’s terms in full and expect responsible-gambling, safety, and privacy information to be easy to find — not buried behind menus. 3. A transparent registration and KYC process We work through the sign-up process ourselves, checking that the operator follows proper Know Your Customer (KYC) checks and offers responsible-gambling controls at the point of registration. 4. Responsible-gambling foundations Membership of GAMSTOP, working self-exclusion, and deposit, loss, and wager limits are mandatory. Every UKGC operator must provide these, so we treat them as a pass-or-fail floor — not as points to be won. We reserve the scored responsible-gambling marks (below) for the things that genuinely differ between operators. How the Sun Factor is weighted Once an operator clears the mandatory checks, we score it across six weighted categories. We updated these weightings in 2026 to reflect what matters most to players: how fast you get paid, and how fair a bonus really is. CategoryWeight (2026)PreviouslyPayments & payouts25%20%Game variety20%20%Bonuses & fairness20% (redefined)20%Responsible gambling15%20%Mobile experience10%10%Customer service10%10% The two things that moved: payout speed carries more weight, because getting your winnings quickly is one of the most common reader priorities and one of the clearest ways operators differ. And bonuses are now scored on fairness, such as wagering terms, win caps, and clarity, rather than headline size, in line with the 2026 rules. Some factors are weighted more heavily than others simply because they have a bigger impact on your experience. The next section breaks down what we look for in each. Payments & payouts — 25% The biggest single factor. We look at: Payout speed — the largest part of this score. We time how long a real withdrawal takes, using the fastest standard method (typically an e-wallet such as PayPal) as our benchmark so operators are compared like for like. Range of banking options — debit cards, e-wallets, and prepaid methods. Deposit and withdrawal limits — flexible enough to suit different budgets. Fees — we note any withdrawal fees clearly. We don’t assume “zero fees”; we report what we find. Game variety — 20% A large library scores well, but quantity isn’t quality. We check the developers an operator works with, flag stand-out and hard-to-find titles, and assess the live-casino range as well as slots. Bonuses & fairness — 20% We analyse the full range of offers for new and existing customers, but under the 2026 rules the terms matter more than the size: Wagering requirements — the lower the better, and capped at 10x. Win caps and restrictions — we mark down low win caps and heavy game restrictions. Clarity — the terms have to be readable, with no nasty surprises in the small print. No-wagering and low-wagering offers score highest. Loyalty and VIP schemes for regular players are a plus. Responsible gambling — 15% Beyond the mandatory tools every operator must have, we score the quality and depth of what’s offered — proactive reality checks, the ease of setting and adjusting limits, self-assessment tools, cool-off options, and clear signposting to third-party help. Mobile experience — 10% We check how well the mobile site is optimised and run through as many games as possible on mobile. If there’s an app, we review it and read recent Google Play and App Store feedback to spot recurring issues. Customer service — 10% Our ideal operator offers 24/7 live chat plus phone and email, a social-media presence, and self-serve help through FAQs and a help centre. What the scores mean Our published ratings sit in a narrow top band, because we only feature operators that clear our mandatory checks and score well. In practice: 4.5–5.0 — an excellent all-round casino. High marks across payments, games, fair bonuses, responsible gambling, and support, with a strong mobile experience. 4.0–4.4 — very good, with one or two areas (often bonus terms or withdrawal speed) keeping it just off the top tier. 3.5–3.9 — solid but with clear trade-offs: perhaps slower payouts, a thinner game library, or stricter bonus terms. Below 3.5 — does not meet the standard we recommend to readers, and won’t appear in our toplists. Toplist ordering Across our casino section, you’ll find various toplists ranking operators by different criteria; a site might top our mobile-app list but sit fourth for bonuses. We only include high-scoring casinos in these lists; a poorly reviewed operator won’t earn a place on any of them. How often we re-check Ratings aren’t set once and forgotten. We re-test featured casinos on a regular cycle and whenever something material changes, such as a rule change, a new bonus structure, a shift in payout times, or a change of ownership. Each review carries the date it was last tested, and during the 2026 re-score, we’ll flag any rating that has moved because of the new regulations. About the author James Anderson James Anderson is a Betting & Gaming Writer at The Sun. He is an expert in sports betting and online casinos, and joined the company in November 2020 to work closely with leading bookmakers, casinos, and online gaming companies to curate content in all areas of iGaming and sports betting. He previously worked as a Digital Sports Reporter and Head of Live Blogs/Events at the Daily Express and Daily Star, covering football, cricket, snooker, F1 and horse racing. Find James on LinkedIn Remember to gamble responsibly A responsible gambler is someone who: Establishes time and monetary limits before playing Only gambles with money they can afford to lose Never chase their losses Doesn’t gamble if they’re upset, angry or depressed Gamcare – gamcare.org.uk Read our guide on responsible gambling practices. For help with a gambling problem, call the National Gambling Helpline on 0808 8020 133 or go to gamstop.co.uk to be excluded from all UK-regulated gambling websites. Most read in Betting