The Real Cost of Clearing a Bonus: A Guide to Wagering Maths
A headline match of 200% or 300% says little, by itself, about whether an offer is favourable. What it is roughly worth depends on the bonus amount, the wagering requirement, what that requirement applies to, the average house edge of eligible games, game-contribution rules, time limits and any maximum-withdrawal cap.
Two simplified educational estimates give a starting point:
Estimated theoretical loss = required wagering × house edge
Approximate bonus edge = bonus amount − estimated theoretical loss
The first line estimates the long-run theoretical loss from completing the wagering. The second applies only where wagering is on the bonus alone and no other restrictive terms materially change the result. Neither formula predicts any player's outcome or guarantees a profit.
Example one: a modest multiplier on the bonus alone
Suppose a player deposits £100 and receives a £100 bonus, with a 20x wagering requirement applied to the bonus only. Required wagering is £100 × 20 = £2,000. With an average RTP of 98%, the house edge is 100% − 98% = 2%. The estimated theoretical loss is £2,000 × 2% = £40, so the approximate bonus edge is £100 − £40 = £60, which is positive under these simplified assumptions.
Example two: an offer that lands near break-even
Here a £40 deposit earns a £40 bonus, and the 25x multiplier again applies to the bonus only. Required wagering comes to £40 × 25 = £1,000. Eligible games average 96% RTP, which gives a house edge of 100% − 96% = 4%. The estimated theoretical loss is £1,000 × 4% = £40, leaving an approximate bonus edge of £40 − £40 = £0, which is roughly break-even in theory.
Example three: wagering on deposit plus bonus
A £50 deposit is matched with a £50 bonus, but the 35x requirement applies to deposit plus bonus, so the wagering base is £100. Required wagering is £100 × 35 = £3,500. At an average RTP of 96%, the house edge is 4%, so the estimated theoretical loss is £3,500 × 4% = £140. The approximate bonus edge is £50 − £140 = −£90. Because the bonus-only condition is not met here, the figure is just a rough indicator, but it suggests these terms cost more in theory than the bonus adds.
This model loses accuracy when game contribution is below 100%, when RTP varies across eligible games, when a maximum cashout caps winnings, when wagering covers deposit plus bonus, or when a player cannot finish wagering within the time limit. If a promotion or balance is held in a volatile cryptocurrency, its GBP value can shift between crediting, wagering and withdrawal. Stablecoins reduce price movement but do not replace reading the terms. RTP is a long-run statistical average, and short sessions can produce very different results.
