A bonus in an online casino is not a gift but a conditional obligation. The credited amount lands on a separate balance and turns into withdrawable money only once the play-through conditions have been met, and those conditions are described by the wagering requirement.
How the play-through is calculated
The requirement is expressed as a multiplier: turnover in bets must exceed the bonus, and sometimes the bonus plus the deposit, a stated number of times. What matters is the detail rather than the multiplier itself: which base it is applied to, which games count and with what weighting, whether a maximum stake applies while wagering is in progress, and how much time is allowed. Slots usually count in full, table games partially or not at all.
Why the operator needs it
Without play-through conditions a bonus would be a direct payout whose cost could not be forecast. The multiplier, together with the game restrictions, sets the expected contribution of the bonus to turnover and allows the bonus programme to be treated as an acquisition cost. It also acts as protection against schemes in which bonus funds are used for low-risk play.
Where disputes arise
Conflicts rarely concern the multiplier itself. Their source is opaque exceptions: a hidden stake cap, a narrow list of eligible games, a short deadline, or a non-obvious order in which own funds and bonus funds are drawn down. Regulators in a number of jurisdictions require these parameters to be disclosed next to the advertised offer itself.
Clear play-through terms cost an operator less than a stream of support tickets and complaints to the regulator.