This page explains how our calculators work. Every figure comes from simple probability maths that you can check by hand.
The core formula
Expected loss = total wagered x house edge
Total wagered is your average bet times the number of bets. The house edge is the average share of each bet the casino keeps.
A worked example
Suppose you play European roulette with a $25 bet, 60 bets an hour, for two hours. That is $3,000 wagered.
The house edge is 2.70%, so the expected loss is about $81. That equals roughly $40 per hour.
Where the edges come from
A European roulette wheel has 37 pockets and pays 35 to 1 on a single number. The house edge is therefore 1 in 37, or about 2.70%.
Other presets use widely published figures for each game and bet type. Blackjack varies with rules and strategy, so we show a typical figure only.
Limits of any estimate
- Results are averages. Real sessions swing well above and below them.
- Rules, pay tables and side bets change the true house edge.
- Calculators cannot predict, or improve, any single outcome.
For education only. See our disclaimer for the full limits of these estimates.