Start with the wagering base, game contribution and withdrawal rules. Those terms usually matter more than the size of the headline bonus. Use this page when a guide introduces a term you have not seen before.
The maths
Expected value (EV)
The average result a calculation predicts across many comparable attempts. A +£5 EV offer can lose on one attempt. EV is only as sound as its inputs and assumptions. See a worked EV example.
Return to player (RTP)
The proportion of total stakes a game pays back over a very large number of plays. A 96% RTP means an average £96 return for each £100 staked across that long run. It is not a promise about your next £100.
House edge
The part of turnover the game retains on average. At 96% RTP, the simple house edge is 4%. On £20 of fixed turnover that suggests an average cost of 80p before a bonus or other condition changes the picture.
Variance
The spread of actual results around the expected value. A good estimate can still be followed by a poor run. Check the model as well as the result before deciding variance is the whole explanation.
Volatility
How unevenly a game pays. Two games may share an RTP while one pays smaller amounts more often and the other pays larger amounts less often. See the comparison.
Bonus mechanics
Wagering requirement
The amount of qualifying stakes needed before bonus funds or winnings can be withdrawn. A £10 bonus at 10x bonus-only wagering needs £100 of qualifying turnover at full game contribution. Read what the multiplier applies to; do not assume the deposit is part of the base. Work through the terms.
Game contribution
The share of a stake that counts towards wagering. At 10% contribution, £10 of play clears only £1 of a requirement. Eligible games may have different rates.
Qualifying wager
The stake or turnover you must complete to trigger a reward. Check eligible games, maximum stake, time window and whether the wager must settle before the reward arrives.
Maximum bet
The largest permitted stake while an offer or bonus is active. A game's own stake limit can be higher than the promotion's limit. The offer rule is the one you must follow to qualify.
Free spins
Spins paid for by a promotion, often at a fixed stake and on a named game. Their value depends on the game's return and on whether winnings become cash or bonus funds with further wagering.
Sticky and non-sticky bonuses
A sticky bonus is tied to a balance that may include your deposit. A non-sticky or cash-first structure can keep balances separate, but the exact withdrawal rights vary by offer. Read the live terms before assuming you can remove your deposit and keep the bonus.
Offer and account labels
Risk-free label
On this site it describes an offer with limited exposure of your own money under the stated conditions. It does not remove eligibility errors, game variance or withdrawal restrictions. Check the worst plausible outcome, not just the label.
Reload or recurring offer
A reload is aimed at an existing customer. A recurring offer resets on a schedule. Opt-in, qualifying windows and reward terms can change, so check each use. Learn how to assess one.
KYC and identity checks
Checks used to verify your age and identity, and sometimes to meet other legal obligations. Use the operator's official channel to supply requested information. Read the account verification lesson.
When an offer term is unclear, stop at the operator's current terms rather than guessing from a glossary. If the term affects eligibility or withdrawal and you cannot resolve it, leave the offer alone.