What a 400% deposit bonus adds, in plain arithmetic

A 400% deposit bonus sits at the top of the welcome ladder, where the multiples run largest: for every £10 deposited, the operator adds £40 of bonus funds, so a £50 deposit becomes a £250 playing balance. That fivefold balance is where honest arithmetic starts, not where it stops. Four figures decide what the offer is worth, and the advert carries only the first: the deposit, the match percentage, the wagering multiple and the conversion cap.

The £250 does not behave like one pot. £50 of it is your own money, withdrawable under the operator's normal rules. The £200 on top is bonus balance, and it lives under its own regime: a wagering multiple counts the stakes you place before any of it releases, a maximum stake clause limits how fast it can be turned over, an expiry bounds the time you have, and a conversion cap bounds what it can become. The fivefold figure describes the balance you would see on screen for a while; the terms describe the money you could leave with.

The model below runs the match at six deposit levels, with turnover priced at 40x on the bonus alone and at 40x on deposit plus bonus, because the terms in this bracket split between those two bases.

Figures are category-typical and modelled; a payment desk's own terms govern.

The 40x multiple is an assumption, stated as one: match funds at this end of the market typically carry 35x to 45x, so 40x sits mid-band. Read the basis line in the terms before opting in, because the gap between the last two columns is a quarter of the turnover again.

The turnover the fourfold headline creates

Turnover is the ladder under the headline. The worked example: deposit £50, receive £200 of bonus funds, and the terms ask 40x before the bonus releases. Forty times £200 is £8,000, the total value of the stakes to be placed, win or lose, before the balance stops being bonus money. We take 40x because that is what this part of the market asks, mid-band in the 35x to 45x the bracket usually prints; at 30x the same bonus asks £6,000, and at 50x it asks £10,000.

The basis matters as much as the multiple. Where the terms apply 40x to deposit plus bonus, the same £50 deposit creates £10,000 of required stakes, a quarter more. The headline never prints the basis; it sits a line deep in the bonus terms, beside phrases such as wagering contribution and eligible games. Two offers can both say 400% and differ by thousands of pounds of required play.

Time turns the turnover into a schedule. At a £5 stake, the top of the maximum-stake band this part of the market tends to print, £8,000 is 1,600 spins, hands or rounds. At eight seconds a round, a fair working pace for an online slot, that is roughly three and a half hours of continuous play. Take the multiple to 50x and the count passes 2,000 rounds. The stakes count the same whether each round wins or loses, which is why the ladder never shortens when the balance does.

The ladder in one figure

The chart takes the £200 bonus from the worked example and shows what the multiple alone does to the required stakes. Nothing else moves between the bars: same deposit, same match, same balance. Only the multiple changes, and the ladder changes with it.

Read left to right, the bars add £1,000 of stakes for every five points of multiple. The percentage in the headline never moves; the ladder under it does. That asymmetry is the reason this page prices the multiple before the match, because the match is printed in forty-point type and the multiple is printed in the terms.

Caps and expiry: the real limits

The percentage sizes the balance; the cap and the expiry decide what it is worth. Take the conversion cap first, as a model with its assumption printed: suppose the terms convert no more than £100 of bonus winnings into withdrawable cash. Under that reading, the £200 the fourfold headline adds can release at most £100, whatever the on-screen balance says. A fourfold match with a £100 cap on a £50 deposit is, in withdrawal terms, a two-to-one offer wearing a four-to-one badge.

The expiry is the second limiter, and it is where a big percentage becomes a demanding schedule. We take 30 days as the modelled window; where the terms print seven days instead, £8,000 of turnover compresses to about £1,143 of stakes a day, every day, for a week, at the maximum stake allowed. Miss the window and the standard clause removes the bonus balance and any winnings built on it that have not converted.

The maximum stake clause ties the schedule down. A band of £2 to £5 is where this bracket tends to set it, and the clause carries teeth: stake above it while bonus funds are in play, and the terms commonly treat the breach as forfeiture of the bonus and everything won with it. Three clauses, none of them in the advert, do more limiting than the percentage ever does.

The sticky reading

There is a stricter way to read the arithmetic, and the terms decide which one applies. Under the sticky reading, the bonus balance is play money that never leaves the account: you can stake it, win with it and watch it move, but a withdrawal request takes it off the table. What leaves is your own deposit plus whatever the bonus play has converted, subject to the cap, once turnover is complete.

Under that reading, the fivefold balance is a working balance, not a prize. The £50 deposit stays yours; the £200 is a stake engine that has to survive its own ladder. If the conversion cap sits at £100, the fourfold headline is worth at most a further £100 of withdrawable money on a £50 deposit, and the honest ratio between money in and money out is smaller than the badge suggests.

Not every package is sticky. Some release winnings to the cash balance as turnover completes, and some run a parachute structure in which the bonus drops away only if you withdraw early. The distinction lives in a single line of the bonus terms, often under maximum withdrawal or bonus forfeiture, and the fourfold headline reads identically in every version. That is why the reading, not the percentage, is the first thing to establish.

Why the biggest percentages ride on the tightest small print

A headline percentage is free to print; the terms are what the operator actually funds. A 100% match with a 20x multiple, no cap and a generous expiry can cost less to honour than a 400% match at 45x with a conversion cap and a seven-day clock, because the cap and the clock bound the payout while the percentage only sizes the balance. The fourfold headline is a pricing decision, and the small print is the other half of the price.

The pattern runs across the bracket: the largest multiples tend to travel with the longest wagering, the shortest expiries and the tightest conversion rules, while the plainest terms sit on the smaller matches. The reason is structural. The percentage is the part of an offer built to be compared, so it is the part built to grow; the clauses are the part built to be accepted, so they are the part built to tighten.

The method follows from it. Price the withdrawal you could actually make: deposit, times the match, through the multiple, against the expiry, cut by the cap, at the maximum stake. A banking desk at this end of the market rarely prints the cap beside the percentage, and offers of this sort rarely publish the resulting figure anywhere the advert can reach. The gap between the two numbers is the cost of the fourfold.

The British baseline beside the fourfold

The table below puts the British baseline first: rows carrying a UK Gambling Commission licence, with welcome offers measured in free bets, modest match ranges and spins at 10p. After them come the offshore rows, the bracket where fourfold and fivefold headlines concentrate, and where the licence column changes with them.

Figures are category-typical ranges compiled from operator-published terms at the time of writing, not quotes of any single promotion. Rows carrying a UK licence are the British baseline shown for comparison; none of them are claimable at the offshore offers this page discusses.

Two structural differences stand out. The licensed rows run on debit rails only, because credit cards have been banned for British gambling since 14 April 2020; the offshore rows are not bound by that ban, and several of them list credit cards outright. The welcome offers separate the same way: the licensed bracket prices in tens of pounds, the offshore bracket prices in hundreds, and the wagering column steepens as the offers grow.

What a UK licence would have bought you

Fourfold headlines concentrate in the offshore rows of the table above, and the licence column explains why the comparison matters. Providing remote gambling facilities to consumers in Great Britain requires an operating licence from the Gambling Commission, and unlicensed provision is an offence under the Gambling Act 2005. The point of restating that here is not to police anyone; it is that every protection in the paragraphs that follow attaches to the licence, and an operator without one carries none of them.

A British licence would have bought a specific list. Identity verification before any gambling, under the anti-money-laundering rules, and age checks before play. Gamstop, the free national self-exclusion scheme, covering the account, with a minimum term of six months, one year or five years that cannot be ended early while it runs. Access to IBAS, the free independent adjudicator, where a dispute over a withdrawal or a forfeited bonus cannot be settled with the operator. Debit-only rails, because the credit card ban binds licensees. A regulator with enforcement powers at the end of the complaint.

The tax position travels with the licence too. British remote gaming operators pay Remote Gaming Duty at 21% of gaming yield, rising to 22% from April 2027, and player winnings are not subject to income tax. Offshore operators pay what their own jurisdiction asks, and the player gets what that jurisdiction provides; for a Curaçao licence claim, the operator's own footer is where the promise is made, and this site treats any such claim as unverified until a register lookup records it.

None of this makes a fourfold offer unlawful to read about, and the list is not a set of rules the offer is breaking. It is a price list. Those protections are what the licence buys, the fourfold headline is what the gap offers instead, and the wagering terms are where the difference is actually paid.