Game contribution percentages are directly related to wagering requirements. For example, if an online casino has a 10x wagering requirement of the bonus received in order to withdraw the bonus funds as cash, the next part of the wagering requirements to keep in mind is the game contribution percentages. Basically, game contribution percentages indicate that not every game is treated equally toward a wagering requirement. Generally speaking, slots are treated at 100%, meaning that every $1 wagered on slots will count as $1 toward the wagering requirement. However, some games can be as low as 10%. This means that for every $1 wagered, only $0.10 for that game will be counted toward the wagering requirement. So, in reality, the wagering requirement can quickly balloon based on whatever games you enjoy playing.