Poker Risk of Ruin Calculator
Calculate your probability of going broke based on your bankroll size, win rate, and variance to ensure proper bankroll management.
Formula:RoR = e^(-2 × WR × BR / σ²)
Your total poker bankroll
Standard buyin for your stakes (optional)
Your expected win rate
Typical: 70-90 for cash, 100-150 for tournaments
Try These Examples
Quick-start with common scenarios
Bankroll Simulator
Monte Carlo simulation with 1,000 iterations
$
Your initial capital
%
Your expected advantage
%
Percentage of bankroll per bet
Total bets to simulate
Understanding Risk of Ruin
Risk of Ruin (RoR) is the probability that you will lose your entire bankroll before your edge can overcome variance. It's the most important metric in professional bankroll management.
The Formula: RoR = e^(-2 × WR × BR / σ²), where WR is win rate in BB/100, BR is bankroll in BBs, and σ is standard deviation in BB/100.
Key Insight: Win rate has an exponential effect on RoR. This is why improving your game (increasing WR) is more powerful than just adding to your bankroll.
Important Limitations: This formula assumes:
- You never withdraw from your bankroll
- You play at the same stakes forever
- Your win rate remains constant
- Results follow a normal distribution
Real-world poker involves stake changes, withdrawals, and skill development, so use this as a guide rather than an exact prediction.
Frequently Asked Questions
What is an acceptable risk of ruin?
Most professionals target <5% risk of ruin for their main stakes. Recreational players might accept 10-15%. A $5,000 bankroll with 5% RoR means you have a 95% chance of never going broke.
How does win rate affect risk of ruin?
Win rate has an exponential effect on RoR. Doubling your win rate from 3 to 6 BB/100 can reduce your RoR from 20% to under 1%. Breakeven players (0 BB/100) have 100% RoR regardless of bankroll size.
What if my risk of ruin is too high?
You have three options: 1) Move down in stakes to increase effective bankroll, 2) Add more money to your bankroll, or 3) Improve your win rate through study. Moving down is usually the safest option.
Does the RoR formula account for withdrawals?
No. This formula assumes you never withdraw. If you take money from your poker bankroll regularly, your effective RoR is higher. Many players use separate life/poker bankrolls to avoid this issue.
Is a higher win rate always better for RoR?
Yes, but there are practical limits. Moving up in stakes to chase higher hourly might decrease your edge. A 5 BB/100 winner at $1/$2 has lower RoR than a 2 BB/100 winner at $2/$5, even with less hourly.
How this works
Calculations follow the published mathematics of the game — combinatorics for cards, probability theory for dice, and expected-value accounting for wagers. Results are verified against independent references (primarily Wizard of Odds). No calculation here is an opinion or recommendation; it is arithmetic applied to the rules of the game.
What this tool can’t do
When to consult a professional
This tool computes probability and expected value. It is not a betting system and cannot predict the outcome of any individual wager. If gambling is causing problems for you or someone you know, call the National Problem Gambling Helpline at 1-800-GAMBLER.
Sources
- [1]Wizard of Odds — Michael Shackleford, ASAIndustrywizardofodds.comAccessed Apr 21, 2026
Actuary; widely cited casino-game probability reference. Used for house-edge and EV verification.
- [2]National Council on Problem GamblingOfficial sourcencpgambling.orgAccessed Apr 21, 2026
Responsible-gambling guidance and 1-800-GAMBLER helpline.
Joseph OrdunaFounder & Software Engineer
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).