A thought experiment about risk
The Coin Toss Casino
Imagine a casino with one game: a coin flip. Call it right, you double your money. Call it wrong, you lose. The odds are perfectly fair — 50/50.
Your goal is simple: win $100 a day. That's it. $100 × 365 days = $36,500 a year.
Your strategy: start by betting $100. If you win, take your $100 profit and go home. If you lose, double your bet. Keep doubling until you win back your losses plus your $100. Then go home.
The question is: how much money do you need in your pocket to guarantee this works?
Watch 365 days of Martingale betting unfold in real time
See every coin flip, every doubling bet, and the moment the bankroll runs dry.
Adjust the scenario
Tweak these numbers and the charts below will update automatically.
The most money you're willing to put at risk
50/50 — truly fair
Running it many times shows the range of possible outcomes (100–2,000)
On a typical run, your biggest single-day risk was:
—
In the worst 1-in-20 runs, your biggest single-day risk reached:
—
Simulations where you went broke:
—
Your Daily Risk Over One Year
Each spike is a bad losing streak that day
Computing…
Range of Outcomes Across All Simulations
Each bar shows how many simulations hit that peak risk level