A bonus headline gives you one number. You need the terms behind it to work out whether that number is worth anything.
Take a 100% match up to £200. Add a 40x playthrough on the bonus, a 30-day clock, a 5x cap on winnings from it, and a rule that counts slots at 100% and live tables at 10%. The £200 becomes a marketing figure and your realistic return drops to something far smaller. Operators publish those conditions before you deposit, because the UK Gambling Commission writes the duty into their licence.
Clear a £100 bonus at 40x and you must stake £4,000 before a penny converts to withdrawable cash. Our guide to what wagering requirements demand traces where that figure comes from, and why the deposit-plus-bonus version costs you more than the bonus-only one.
Run a worked example and the shape of the offer appears. Deposit £100, take a £100 bonus at 35x on the bonus alone, and the playthrough comes to £3,500 of staking. At £1 a spin on a 96% slot that is 3,500 spins and roughly £140 in expected loss against a £100 bonus. Move the multiplier onto deposit plus bonus and the target doubles to £7,000, along with the expected cost.
Game weighting decides how much of each stake counts. Slots contribute in full at most sites, live blackjack at a tenth or nothing at all, and a few operators exclude table games from bonus play altogether. Spin £1,000 at live roulette on a 10% contribution and you have cleared £100 of a £4,000 target.
Max bet clauses catch people next. Terms cap a single spin or hand at £5 while a bonus is live, and a stake above that cap lets the operator void the bonus and the winnings attached to it. That clause sits in the small print on the page, and it appears in most UK offers.
Expiry dates finish the job. A 30-day window sounds generous until you match it against contribution rates and the hours you play. Compare how these offers work across a few UK sites and you will find windows running from seven days to 90.
Reading the terms first takes about ten minutes. Work through them in one order: wagering, base, weighting, max bet, cashout cap, expiry. Those six lines answer everything that matters, and the rest of the page is decoration.
Do the arithmetic before you claim. A £100 bonus at 40x on a slot with 96% RTP costs around £160 in expected losses: £4,000 of staking at a 4% house edge. Work out the cash value of a bonus with that method and most of the market collapses.
Return-to-player percentages matter more than the headline figure suggests. A 96% return sits close to break-even on a single spin and grinds you down across thousands of them. Our piece on why slots owe you nothing covers how a 4% edge compounds over a long session.
A bonus that costs more in expected losses than it hands you in credit is a bad trade. Work out the true cost of a bonus before you claim and you will sort the offers into two groups.
Expected loss is an average, and short sessions swing hard. A 96% slot can pay above its stated RTP across 200 spins and well below it across 5,000. Plan for the run you will play.
Sticky and non-sticky bonuses change the sums again. A sticky bonus leaves your balance at withdrawal, which cuts what you keep by the size of the bonus. With a non-sticky offer, what the playthrough costs you is the expected loss on the staking and nothing more.
One clause can undo all of it. Cashout caps, win limits of 5x the bonus, and rules on bonus funds expiring at withdrawal all sit above the RTP maths, and the fine print that overrides carries more weight than any number on the game itself.
Rankings of which bonus types hold value put cashback and low-wagering free spins above the large match percentages, because the terms attached to them bite less. A 10% cashback deal with no wagering beats a 200% match at 50x on almost every measure.
Match bonuses carry the biggest numbers and the longest playthroughs. A 50x multiplier on a £200 bonus means £10,000 of staking, and the cashout cap usually lands between 3x and 6x the bonus.
Free spins arrive with a fixed value per spin, often 10p, and a separate wagering figure attached to any winnings. Twenty spins at 10p carry £2 of entertainment and a withdrawal condition worth reading.
No-deposit offers hand you £5 to £10 in bonus credit with no card on file. Your withdrawal cap sets the value here, and where no-deposit offers come from does not change that arithmetic.
Check the cap before claiming a no-deposit deal, because a £100 win capped at £20 is a £20 win. The terms sit on the same page as the banner, and they take two minutes to read.
Promo codes add another layer. A code that lifts a match percentage carries its own conditions, so read the SlotoSport code conditions to see how one line in a promotion shifts the wagering base.
Score each offer on four numbers: multiplier, base, max bet, cashout cap. Write them in a column. Offers that look identical on a banner separate on those four figures, and the best one often carries the smallest headline.
Most of the usual bonus mistakes happen in the first hour: a spin placed above the max bet, a table game opened instead of a slot, a second bonus claimed on the same account, a withdrawal requested while the playthrough sits unfinished.
Operators also write abuse clauses into their terms. Playing a restricted game with bonus funds, hedging across two accounts, or holding more than one account per household can void a win, and those clauses are broad enough to catch an honest mistake.
Compare operators and the differences show up fast. Our Night Win verdict takes one site's terms apart clause by clause, which helps when you want to see how a wagering base gets built.
Our Voodoo Dreams verdict does the same for a second operator, and the contrast in game weightings is the useful part.
The basswin review rounds out the set, so you can see how much max-bet limits and contribution tables vary between sites.
Payment methods matter as much as the terms. The credit card ban has blocked cards for gambling deposits since April 2020, so your deposits come from a debit card, PayPal, Apple Pay, Google Pay, Trustly, or Paysafecard.
Every operator on the UK market holds a Gambling Commission licence, so the same baseline rules apply: published terms, tested RTPs, and access to an alternative dispute resolution service when a complaint goes unanswered.
Check the licence number, the terms page, and the payments page before you hand over card details. You can put a UKGC licence and a bonus terms page side by side at Casino Castle, and the exercise takes five minutes.
Set a deposit limit before your first spin and a session reminder at 30 minutes. GamStop blocks you from every UKGC-licensed site through one registration, and the block holds for a minimum of six months. BeGambleAware and GamCare run free helplines if the betting stops feeling like a choice.
You can spot trouble earlier than you think. Our breakdown of how problem gambling builds tracks the shift from planned stakes to chasing losses, and you can spot that change in your own staking history first.
Run the numbers on each offer, claim the ones that clear, and keep your stakes at a level you would be happy to lose.
