First choose the correct base: bonus alone or deposit plus bonus. Multiply it by the wagering factor to obtain eligible turnover. Then account for the game’s contribution: at 50%, only half of each qualifying stake counts. At 0%, that game cannot advance the requirement.
For a bonus of 50 at 20×, eligible turnover is 1,000. With 50% contribution, the arithmetic requirement is 2,000 in qualifying stakes. Deadlines, excluded actions, maximum bets and balance rules still apply. The calculator below compares the two bases at the selected contribution; it does not simulate your future balance.