Five losses in a row is not bad luck. On a strategy that wins half its trades, a five-loss streak inside a hundred trades is close to certain. Seven in a row at a 40% win rate is an ordinary month.
Risk of ruin is the probability that one of those normal streaks removes your account before your edge has a chance to show up. It is the difference between a trader with an edge keeping it and losing the account that held it.
The one calculation
Full losses of room = drawdown allowance ÷ loss per trade
On a $100,000 account with an 8% maximum drawdown, you have $8,000. That is it — the entire buffer.
| Risk per trade | Loss per trade | Losses until the account is gone |
|---|---|---|
| 2.0% | $2,000 | 4 |
| 1.0% | $1,000 | 8 |
| 0.5% | $500 | 16 |
| 0.25% | $250 | 32 |
Four losses is not a buffer. It is a coin landing the same way twice. Sixteen is a bad fortnight you trade through.
The daily limit is the tighter constraint
The maximum drawdown ends the account, but the daily limit ends the day — and it does so far more often. On a 3% daily rule:
- 1.5% per trade → two losses locks you out
- 1.0% per trade → three losses
- 0.5% per trade → six losses
Ask yourself honestly what a bad session looks like for you. If the answer is three losses, then risking 1% guarantees you will hit the daily floor on a completely normal day. Size so a normal bad day cannot reach it, and set a personal stop well before the hard one.
Correlation multiplies risk you did not intend
Three long positions on EUR/USD, GBP/USD and gold during a dollar move are not three trades. They are one trade in three costumes, and they lose together.
Count correlated positions as a single risk unit when you plan the day. Two positions at 0.5% each driven by the same catalyst is a 1% trade, and it should occupy 1% of your allowance in your own bookkeeping.
Floating losses count
This is where traders get caught. Most firms — including us — evaluate the drawdown on equity, which includes open positions. A basket of trades floating $700 in the red has already used $700 of the allowance, even if you intend to hold them until they recover.
Your dashboard shows the remaining room in dollars in the Where you stand band. Size the next trade against that number, not against the balance.
Lowering ruin risk without trading less
Cutting risk per trade is the direct lever, but not the only one:
- Improve the average win relative to the average loss. A profit factor above 1.5 shortens the recovery each streak needs.
- Cap the number of trades per session. Most ruin arrives from attempts to repair a loss, not from the loss.
- Stop after a fixed number of losses. Two is the number most consistent funded traders use.
- Reduce size while the equity curve is below its recent high, and restore it after a new high, not after a good feeling.
The practical target
Keep at least twelve to sixteen full losses of room against the maximum drawdown, and at least four to six against the daily limit. On an 8% / 3% ruleset that lands you at 0.5% per trade — which is exactly where most traders who get paid repeatedly end up sitting.
Run your own numbers with the risk tools, then read expectancy to see how much trading your edge actually needs to work.