Risk of Ruin Risk of Ruin
The probability of losing your entire set bankroll. It varies greatly with bet size, a game's volatility, and play time, and when RTP is below 100%, it approaches 1 the longer you play.
| English | Risk of Ruin |
|---|---|
| Classification | Math & Probability |
| English | Risk of Ruin (RoR) |
| Category | Math · Probability |
| Definition | The probability of losing the whole bankroll |
| Factors | Bet size relative to bankroll, volatility, play time, RTP |
| Games with RTP below 100% | Ruin probability reaches 100% if played indefinitely |
| Related | Volatility, variance, bankroll management |
Overview
Risk of ruin is the probability of losing all of the funds (bankroll) you have. It started as a math concept for calculating an insurance company’s ability to pay claims, but it is also widely used in gambling and investing.
For a game like a slot, where the RTP is below 100%, the expected value is negative, so if you keep playing endlessly, the probability of ruin eventually approaches 100%. That’s why the practical question is “what is the chance of running out of funds within a set number of spins?”
What increases the risk of ruin
| Factor | Risk of ruin | Reason |
|---|---|---|
| The larger the bet relative to the bankroll | Grows | Bankroll is wiped out after just a few losses in a row |
| The higher the volatility | Grows early on | Long losing stretches with no wins occur |
| The longer you play | Grows | The house edge accumulates |
| The lower the RTP | Grows | Average loss rate speeds up |
Simulation results
These are two hypothetical games with the same 96% RTP, each simulated 20,000 times with a bankroll of 100 units and a bet of 1 unit per spin.
| Spin count | Low-volatility ruin | Low-volatility profit | High-volatility ruin | High-volatility profit |
|---|---|---|---|---|
| 200 spins | 0% | 25.9% | 52.6% | 27.2% |
| 1,000 spins | 4.3% | 9.7% | 77.8% | 19.1% |
| 5,000 spins | 95.4% | 0.2% | 92.2% | 7.4% |
The low-volatility game (2x with 48% probability) almost never goes broke at first, but by around 5,000 spins, 95% of players are wiped out. The high-volatility game (100x with 0.96% probability) sees half of players wiped out within 200 spins, yet the share of players who end up in profit stays higher. Either way, the longer you play, the greater the risk of ruin.
Effect of bet size
Even with the same bankroll, lowering your bet makes it take longer to go broke. A bankroll worth 100 bets and one worth 20 bets are completely different games. High-volatility slots in particular have long gaps between wins, so if your bankroll covers only a few dozen bets, you’re more likely to finish without ever seeing a bonus.
Things to remember
- The only ways to reduce the risk of ruin are to lower your bets or set a time limit for play. No betting method can turn the expected value positive.
- Raising your bets to win back lost money (chasing losses) sharply increases the risk of ruin.
- The basic rule for slots is to play only with money you can afford to spend on entertainment. To check how a game works without real money, you can use a free demo.