Risk of Ruin & Kelly Calculator

Find your mathematical probability of going broke and discover optimal GTO stake sizes based on your personal winrate and variance.

Simulation Inputs

BB/100
BB/100
$
%
$BB

Risk of Ruin Analysis

Calculated Risk of Ruin
20.96%
Certain Ruin (Dangerous)

The probability that you will bust your current bankroll playing under these parameters over an infinite horizon.

Kelly Sizing Recommendations

Quarter Kelly (Recommended)
$5,120 (2560 BB)
Deci Kelly (Very Safe)
$12,800 (6400 BB)
Half Kelly (Aggressive)
$2,560 (1280 BB)
Full Kelly (Highly Volatile)
$1,280 (640 BB)
Your bankroll is below the recommended safe threshold (Quarter Kelly). It is highly advised to move down in stakes (Shot-Down) to mitigate ruin risk.

Stakes Management Guide

Recommended Stake Level (Target 5% RoR)
$1.04 / Big Blind

To maintain your target risk of ruin (5%) with this bankroll ($2,000), it is recommended to play stakes no higher than $1.04 big blind (e.g., $0.52/$1.04) per session.

Risk of Ruin vs Bankroll Curve

Curve showing exponential reduction in risk of ruin as bankroll grows.

0%25%50%75%100%$0$1536$3072$4608$6144You: $2000 (21.0%)

Bankroll Simulator (Monte Carlo)

5 randomly simulated bankroll trajectories over your next 100 periods (sessions or 1,000-hand intervals) under your specified winrate and variance. (each simulation period: 1,000 hands)

$0$4,580$9,161$13,741$18,321020406080100

Want to Track and Analyze Your Poker Game?

On My Bankroll, you can log sessions, track your bankroll, access advanced analytics, and get Claude AI GTO feedback for free.

What Are Risk of Ruin and the Kelly Criterion?

Risk of Ruin is the mathematical probability of losing your entire bankroll given your win rate, variance (standard deviation), and current bankroll size. Even a solidly winning player can go broke playing stakes too high for their roll — short-term variance alone is enough. That's why professionals treat bankroll management as seriously as playing skill.

The Kelly Criterion tells you the optimal fraction of your bankroll to risk in order to maximize long-term growth. This calculator combines both metrics and recommends the blind level you can safely play with your current bankroll.

How to Use

  1. Enter your win rate (bb/100 or hourly). If you don't know it yet, track your sessions with My Bankroll to measure it.
  2. Enter your standard deviation. Typical no-limit hold'em cash games run around 80–120 bb/100.
  3. Enter your current bankroll and the stake you play.
  4. Review your risk of ruin and the recommended stakes — keep your risk of ruin under 5% by moving stakes up or down.

Frequently Asked Questions

What risk of ruin percentage is acceptable?

Most professionals recommend staying under 1–5%. If your risk of ruin exceeds 10%, that's a warning sign to move down in stakes or top up your bankroll. If poker is your main income, a stricter threshold under 1% is safer.

What is the Kelly Criterion?

A formula that computes what fraction of your bankroll to risk to maximize long-term growth, based on your edge and variance. Because poker variance is high, most players use half-Kelly rather than full Kelly for an extra margin of safety.

How many buy-ins do I need for cash games?

A common guideline is 20–50 buy-ins for cash games and 100–200 for tournaments, whose variance is far higher. The right number depends on your personal win rate and standard deviation — this calculator computes it from your own data.