Bonus Max Bet Rule: Stake Limits, Breaches and Auto-Play Risk
The bonus max bet rule is a cap on how much you can stake on a single spin or bet while bonus funds are in your balance. If you go over it, the casino can remove your winnings, sometimes along with the bonus. Check the cap in the terms before your first spin, and check your stake setting before every session.
This article is part of our slot guides, written to explain the maths and mechanics behind every spin.
This guide lists the caps we found in published UK terms, explains why breaches void winnings and shows how to keep your stake under the line. It is part of our slot guides and sits beside the explainers on wagering requirements and bonus game weighting.
What is the bonus max bet rule?
When you play with a bonus, the terms usually set a top stake per spin or per round. It applies while any bonus funds are in the balance, and for some offers also while a wagering requirement is outstanding. The rule is a condition of the bonus, so the casino enforces it through the bonus terms and not through the game itself.
Most players first meet it at the moment of a breach. Do not assume the game will stop an over-cap bet, because the cap is a term of the offer and the casino can apply it when you try to withdraw.
That is why the stake setting matters more than the game you choose.
What are typical max bet values?
The figures below come from welcome-offer terms read on 24 October 2026 at UKGC-licensed casinos. They are single examples, not an industry average, and each operator sets its own.
| Source | Stated cap | Note |
|---|---|---|
| One casino’s welcome offer terms | £15 per spin on slots | The terms prohibit "betting more than £15 per spin on slots while using bonus funds". |
| A second casino’s welcome offer terms | €5 per spin or local equivalent | The UK page states "Max Bet/Spin €5 or local equivalent". |
| A third operator’s welcome offer help article | Not stated | The article gives no max bet figure. |
| Gambling Commission online slots limit | £5 per game cycle (25 and over), £2 (18 to 24) | A regulatory stake limit, not a bonus rule. In force from 9 April 2025 and 21 May 2025 respectively. |
Sources: operators’ published terms read 24 October 2026; Gambling Commission online slots stake limit guidance.
On the face of it, a bonus cap of £15 sits above the £5 per game cycle limit on UK online slots, so on those slots the statutory limit is the tighter one. The bonus cap still matters for other products, and any bonus cap below the statutory figure bites first.
Why do operators void winnings after a breach?
The cap exists to stop you clearing a requirement with a few large bets that could return a big prize in one spin. A bonus priced on the assumption of steady stakes becomes much more expensive if a player can raise the stake on a hot streak. The casino therefore treats a breach as a failure to meet the offer’s terms and removes what the bonus produced.
The remedy in the terms can be severe. Terms can allow the casino to cancel the winnings, the bonus, or both, and how far it goes is for each operator’s terms to say.
The Gambling Commission has flagged this area. In February 2022 it said it had found promotions for online games with "terms entitling a licensee to void real money winnings if a customer inadvertently breaks staking rules", as part of its update on fair terms and practices.
What counts as a breach of the max bet rule?
- A single spin or bet above the stated cap while bonus funds are in the balance.
- A combined stake across several lines or ways that adds up to more than the cap, where the terms measure the total.
- A stake placed through a feature such as bonus buy, if the terms count its price as the stake.
- A bet placed after the casino converts your balance, for example when your cash runs out and bonus funds take over.
The list is a checklist of questions, not a guarantee of how each operator reads its own terms. Look for the words "maximum bet", "maximum stake" and "per spin" and note whether the cap is per spin, per round or per hand.
What does the Gambling Commission say about max bet terms?
The Commission’s guidance on promotional play restrictions says terms must "clearly specify all prohibited types or patterns of play", that operators must not "reserve sole discretion" to decide when a breach happened, and that they must not ban a form of play that was not clearly outlined in advance. If winnings are lost for a breach, "the consumer must be provided with a full explanation of the breach" (promotional play restrictions).
Its guidance on deposits adds that play restrictions cannot be applied to play with your deposit balance unless software automatically stops you breaching them (restrictions on withdrawing deposit and deposit winnings).
Neither page sets a figure. The cap is the operator’s to choose, and the fairness test applies to how it is disclosed and enforced.
How do you check your stake settings?
- Read the bonus terms and note the cap, and whether it is per spin, per round or per hand.
- Open the game before you opt in and look at the stake selector. Set it to a value comfortably below the cap.
- Check the total stake, not only the per-line figure. Many slots show both.
- Look at bonus-buy and gamble features, and leave them alone if the terms count them towards the cap.
- Reset the stake each time you change game, because a title may remember a previous higher stake.
- Take a screenshot of the terms and the stake screen so you have a record.
Do the check again when your cash balance runs out in a cash-first offer, because the bonus may become active at that moment with whatever stake is set. Our sticky vs non-sticky bonus guide explains that handover. For live offers to check against these steps, see the UK slot bonuses compared page.
What is the auto-play risk?
Where auto-play is available, it keeps placing the stake you set at the start. If your stake was above the cap when the bonus became active, every automatic spin is a breach. Nothing flags it to you in the moment.
The same applies if you raised your stake during a winning run and then started auto-play. Reset it first, and use stop conditions so it cannot run unattended.
The simplest safeguard is to play bonus funds by hand, one spin at a time, and to keep the stake at a level you never need to change.
More slot guides
- how online slots work
- RTP explained
- slot volatility explained
- max cashout limits
- live dealer vs RNG
- wagering requirements explained
- bonus game weighting
- sticky vs non-sticky bonuses
- how to value free spins
- wagering requirement calculator
- how crash games work
- Plinko odds explained
- the maths behind Mines
- slots maths course
Frequently asked questions
What is the max bet while a bonus is active?
It is the top stake per spin or bet that the bonus terms allow. The figure is set by each operator, and the examples we read were £15 per spin on slots and €5 per spin or local equivalent.
What happens if I bet over the limit?
The terms usually allow the casino to remove your winnings and sometimes the bonus. The wording is in the bonus terms, and the Gambling Commission expects a full explanation of any breach.
Does the rule apply to my own deposit?
The Gambling Commission says play restrictions cannot be applied to play with your deposit balance unless software stops you from breaching them. If bonus funds and cash are both in the balance, check which one is being used.
Is the limit per spin or per bet?
It depends on the terms. Some set a cap per spin, others per round or per hand. Read the exact wording and measure your total stake, not only the per-line figure.
Can auto-play break the max bet rule?
Yes. Auto-play repeats your stake setting, so if that is above the cap, every spin breaches it. Reset the stake before you start and play bonus funds by hand.
Does the rule apply to free spins?
Free spins are played at a stake the offer sets, so you cannot go over a cap during them. One casino’s help article we read credits its spins at 10p each. The condition can apply to any games you play with the winnings, and our free spins value guide covers how to price the spins.
Responsible gambling. You must be 18 or over to gamble. Set a stake you can afford and a session limit before you opt in, and keep to them even when a bonus is running. GamCare offers free, confidential support on 0808 8020 133, and BeGambleAware provides further guidance. Our responsible gambling page lists the tools available.