Lab note L-01
The score formula, worked through
Every score on this site comes out of one weighted sum. Here are the parts, the reasoning behind each constant, and the complete arithmetic for all 5 casinos.
The sum
score = 0.20·B + 0.30·W + 0.15·S + 0.15·D + 0.20·L
B bonus size, W wagering, S spin value, D min deposit, L licence. Each is scored 0 to 10, so the total also lands between 0 and 10. We keep full precision until the very end and round to one decimal place for display, half up.
The weights add up to 1.00. They were set before any offer was scored and haven't been tuned to produce a particular order. If we ever change them, the change and its date will be recorded on this page.
Each metric, and why its constants are what they are
B Bonus size · weight 20%
10 × min(cash, £100) ÷ £100
Input: Convertible cash: the headline cash bonus, cut to the max conversion where the terms state one.
We score the cash a bonus can actually turn into, not the number on the banner. Where the terms set a maximum conversion, that cap replaces the headline. £100 is a fixed yardstick: an offer that can convert £100 or more scores 10, half of that scores 5. We chose a fixed anchor instead of "best in sample" so that adding or removing a casino never shifts anybody else's score.
W Wagering · weight 30%
10 − 0.4 × multiple, then −1 if any part is due within 7 days
Input: Wagering multiple, plus the shortest deadline anywhere in the offer.
Each 1x of wagering costs 0.4 points, so 10x leaves 6 and 25x would leave nothing. Since 19 January 2026 the Gambling Commission has capped wagering on UK promotions at 10x, so for British offers the multiple part tops out around 6 unless an offer has no wagering at all. The deadline penalty is a flat point for any element that must be cleared in 7 days or less; a short window pushes players into longer, faster sessions, and we'd rather the score reflected that.
S Spin value · weight 15%
10 × min(face value, £20) ÷ £20
Input: Number of free spins × stake per spin (10p assumed and flagged if the terms omit it).
Spin value is the number of spins times the stake per spin. Twenty pounds of face value scores 10. When the terms don't state a stake we assume 10p, the stake used by every offer here that does state one, and flag the result as assumed wherever it's shown. We don't try to predict what spins will return.
D Min deposit · weight 15%
10 × (1 − deposit ÷ £40), never below 0
Input: Minimum qualifying deposit.
A lower entry price scores higher, falling linearly to zero at £40. It's the minimum needed to qualify, not a recommended deposit.
L Licence · weight 20%
8 for the account + register link, +2 if company details are disclosed
Input: UKGC account number with a public-register link; operator's company number and address.
We only list UKGC-licensed operators, so everyone starts at 8 for having a published account number that links to a public-register entry. The last two points go to operators whose company number and registered address appear in the material we captured. It's a transparency measure, not a safety ranking: a UKGC licence is the thing that matters most, and all five have one.
The arithmetic, brand by brand
Inputs are parsed from each offer's terms on every build, so if an operator changes a figure the scores change with it. Rows are in leaderboard order, which is score order.
| Casino | B Bonus | W Wagering | S Spins | D Min dep | L Licence | Total | Equal wts |
|---|---|---|---|---|---|---|---|
| Luna Casino | 5.00£50 convertible | 6.0010x, 30 days | 2.5050 × £0.10 | 7.50£10 minimum | 10.00UKGC 39326 + company no. | 6.36.300 | 6.20 |
| Swift Casino | 2.50£25 convertible | 6.0010x, 30 days | 5.00100 × £0.10 | 7.50£10 minimum | 10.00UKGC 39326 + company no. | 6.26.175 | 6.20 |
| PlayKasino | 0.00no cash bonus | 6.0010x, 30 days | 10.00200 × £0.10 | 5.00£20 minimum | 10.00UKGC 39326 + company no. | 6.16.050 | 6.20 |
| Vegas Mobile Casino | 5.00£1,000 headline, £50 cap | 5.0010x, 7-day part | 5.00100 × £0.10 (assumed) | 7.50£10 minimum | 8.00UKGC 39335 | 6.05.975 | 6.10 |
| The Online Casino | 5.00£50 convertible | 5.0010x, 7-day part | 1.0020 × £0.10 (assumed) | 7.50£10 minimum | 8.00UKGC 39335 | 5.45.375 | 5.30 |
Written out
- Luna Casino: 0.20×5.00 + 0.30×6.00 + 0.15×2.50 + 0.15×7.50 + 0.20×10.00 = 6.300 → 6.3
- Swift Casino: 0.20×2.50 + 0.30×6.00 + 0.15×5.00 + 0.15×7.50 + 0.20×10.00 = 6.175 → 6.2
- PlayKasino: 0.20×0.00 + 0.30×6.00 + 0.15×10.00 + 0.15×5.00 + 0.20×10.00 = 6.050 → 6.1
- Vegas Mobile Casino: 0.20×5.00 + 0.30×5.00 + 0.15×5.00 + 0.15×7.50 + 0.20×8.00 = 5.975 → 6.0
- The Online Casino: 0.20×5.00 + 0.30×5.00 + 0.15×1.00 + 0.15×7.50 + 0.20×8.00 = 5.375 → 5.4
How sensitive is the order?
The top of the table is tight, and we'd rather say so. Luna Casino leads Swift Casino by 0.12 points before rounding. The "equal weights" column above shows what happens if every metric counted the same: the top three would finish level, because spin value and minimum deposit gain influence at the expense of wagering and licence.
Small margins like these are the reason we show the bars and not just the total. Two offers that score 6.2 and 6.1 are built very differently; the right one for you depends on what you want out of it: bonus cash, spins, or the lowest entry price.
What the formula leaves out
- Game choice, software, live casino quality
- Payment methods, withdrawal speed, fees
- Customer service and complaint handling
- Anything that depends on luck, which is all of the outcomes
We leave these out because we can't measure them from the terms, not because they don't matter. The reviews cover what the operators publish about them; the methodology page explains the boundaries in plain terms.