risk8 min read·calculator

Gambling Risk Calculator: Assess Your Session Risk

Risk assessment in gambling goes beyond knowing the house edge. It combines your bankroll, bet size, game volatility, and session length to estimate your probability of going broke, your likely ending balance, and the range of probable outcomes. Our Risk Lab automates this analysis, but understanding the underlying concepts empowers you to make better decisions at any game.

18+ Only. Gambling involves risk. Please gamble responsibly. Learn more →

Understanding Risk of Ruin

Risk of Ruin (RoR) is the probability of losing your entire bankroll during a session. It depends on three factors: the house edge (how fast you lose on average), variance (how much results swing), and the ratio of your bankroll to bet size. With a $100 bankroll and $5 bets at European roulette, the risk of ruin over 200 spins is approximately 20-25%. Reduce the bet to $2 and the risk drops to under 5%. This illustrates why bankroll-to-bet ratio is the most controllable risk factor.

Risk of Ruin ≈ f(House Edge, Variance, Bankroll/Bet Ratio)

•Three factors: house edge, variance, bankroll ratio
•Higher bet-to-bankroll ratio = higher risk
•House edge makes ruin eventually certain (infinite play)
•Shorter sessions = lower risk of ruin
•Bet sizing is the most controllable factor

Optimal Bet Sizing

A common guideline is to never risk more than 2-5% of your bankroll on a single bet. With a $200 bankroll, bets should be $4-10. This gives you enough hands to experience the game without a high probability of going broke. For high-volatility games (slots, single-number roulette), use the lower end. For low-volatility games (blackjack, baccarat), you can use the higher end. The goal is to have enough bets to absorb the inevitable losing streaks while maintaining a reasonable session length.

•2-5% of bankroll per bet is a common guideline
•$200 bankroll → $4-10 bets
•Low volatility games: upper end (5%)
•High volatility games: lower end (1-2%)
•Goal: survive losing streaks without ruin

Planning Your Session

Before gambling, decide three things: your bankroll (money you can afford to lose), your bet size (based on the bankroll guideline), and your session length (time or number of bets). Then calculate your expected loss: Total Wagered × House Edge. If the expected loss exceeds what you are comfortable paying for entertainment, adjust your parameters. Reduce bet size, play fewer rounds, or choose a lower-edge game. Pre-commitment is the most effective responsible gambling tool.

•Set bankroll, bet size, and session length in advance
•Calculate expected loss before sitting down
•Adjust parameters if expected cost is too high
•Pre-commitment reduces impulsive decisions
•Treat expected loss as an entertainment budget

Monte Carlo Simulation for Risk Assessment

Monte Carlo simulation runs thousands of virtual gambling sessions with your exact parameters. Instead of a single expected value, it shows the full distribution of outcomes: best case, worst case, median, and the probability of every outcome between. Our Risk Lab uses this approach to give you a complete picture. It reveals that while the average outcome is predictable (expected loss), individual sessions span a wide range, and understanding this range is essential for managing expectations and bankroll.