Turn odds into pounds and pence
Four calculators for the questions that matter: what a session costs, what a bonus really costs, what odds mean and what happens to a doubling system.
What will a session cost?
Expected loss is your total stake multiplied by the house edge. Change the inputs to see how speed and stake size add up.
What does a bonus really cost to clear?
Wagering tells you how much you must stake. The game’s RTP tells you what that staking costs on average.
Odds converter
Type odds in any format to see the others and the chance they imply.
Martingale reality check
Doubling after every loss feels safe because it wins often. This shows how likely the losing streak that breaks it really is.
Calculator questions
How do I work out how much a casino session will cost?
Multiply the total amount you expect to stake by the game’s house edge. Total staked is your stake per round times the number of rounds, so speed of play matters as much as stake size.
How do I calculate the real cost of a bonus?
Multiply the amount the wagering applies to by the wagering number to get the total you must stake, then multiply that by the house edge of the games you play. Since 19 January 2026, UK-licensed operators cap wagering at ten times.
Does the Martingale system work?
It wins small amounts most of the time, but a run of losses forces stakes to grow quickly until they hit the table limit or your bankroll. The occasional large loss cancels the many small wins, and the house edge still applies to every bet.