Why 50% Odds Still Lead to Massive Gambling Bankruptcy? A Python Simulation

Experiment Overview

On Zhihu a question asks why, despite a 50% win rate per round, many gamblers go broke. To explore this, we built a Python simulation of a dice betting game.

Experiment Idea

Game: dice "big or small", one round per day, ends when the gambler loses all money or the casino closes.

After three consecutive losses the gambler raises the bet by 50%.

The gambler starts with 1,000,000 yuan and bets 20,000 yuan each day.

If bankrupt, the gambler borrows high‑interest loans (estimated monthly rate 5%).

The loan is repaid the next day, assuming a "disciplined" gambler.

Test Steps

1. Create characters

Casino

This is a reckless gambler

2. Create betting round

We use dice instead of cards.

Below is the function implementing the betting round:

Run 100 rounds for a man.

Record daily wins/losses and check for bankruptcy.

3. Data Statistics

Simulating 1,000 gamblers, 167 survived (3 lost, 164 profited) while 833 went bankrupt, an 83.3% bankruptcy rate. The distribution of bankruptcy times is shown below.

Profit of survivors after eight years:

The richest survivor earned 12.5 million yuan; only six earned over 10 million.

Using an estimated 13% annual inflation, the 12.5 million profit after eight years is equivalent to about 5.53 million today.

Conclusion

Bankruptcy rate reaches 83.3%; half go broke within a year.

Gambling profit is random and low; it is not a reliable way to get rich.

The chance of beating the casino is essentially zero.