SlotMonster advertises a $10 FREE bonus. We do not have SlotMonster’s live wagering figure, so we are using 40x only as an illustration, not as a published SlotMonster term.

The arithmetic is the same at every operator. Start with the bonus amount, $10. Multiply it by the wagering multiple, 40x. That produces 400 in required total stakes.

$10 × 40x = 400

That does not mean a player needs 400 in cash. It means the bonus balance must be staked repeatedly until total bets reach 400, subject to the games that count and any other bonus rules. Some games may contribute less, or not at all, so the operator’s current terms always need checking.

To estimate the cost of that turnover, use the RTP. At 96% RTP, the expected loss is 4% of total stakes. On 400 of turnover, the approximate expected cost is 16.

400 at 96% RTP = approximate expected cost of 16

This is only an average calculation. Actual results can be very different over a short run. A player could finish wagering early, or have enough balance to complete it. RTP also does not remove variance.

The wagering multiple gets attention, but the maximum cashout cap often matters more. Even if a bonus balance grows while meeting the requirement, a cap can limit what can be withdrawn. That cap, along with eligible games and any withdrawal conditions, can change the practical value of the offer more than the headline 40x figure.

Most no deposit bonuses do not convert directly into withdrawable cash. They are usually a free attempt under rules, rather than income. Readers can repeat this method for any offer: take the stated bonus, apply the published wagering multiple, then estimate the turnover cost using the listed RTP.

The longer explanation: https://casinonodeposits.com/wagering-requirements-explained/
SlotMonster review: https://casinonodeposits.com/review/slotmonster/