Most traders know that losses hurt. Fewer realise that the arithmetic of recovery is lopsided: the deeper you fall, the disproportionately larger the gain needed to get back. Understanding drawdown math changes how you think about risk, and is probably the most persuasive argument for keeping each trade small.
What is drawdown?
Drawdown is the decline in your account from a peak to a subsequent low, usually expressed as a percentage. If your account climbs to 10,000 and then falls to 8,500, you are in a 15 percent drawdown. Maximum drawdown is the largest such decline over a period and is a standard way to describe the pain a strategy has caused. Drawdowns are not a sign something is broken; every strategy has them. The question is whether yours is survivable.
The asymmetry
If you lose a fraction L of your account, you need a gain of L / (1 - L) on the remaining balance to return to the start. The table below uses simple, illustrative figures.
| Loss from peak | Gain needed to recover |
|---|---|
| 5% | 5.3% |
| 10% | 11.1% |
| 20% | 25% |
| 30% | 42.9% |
| 40% | 66.7% |
| 50% | 100% |
| 75% | 300% |
| 90% | 900% |
The reason is simple: gains apply to a smaller base. Lose half of 10,000 and you have 5,000; you now need that 5,000 to double just to get back to 10,000. Up to about 10 percent, the gap is small, but past 30 percent it grows quickly. Professional risk managers focus on avoiding deep drawdowns for exactly this reason.
What a losing streak does to an account
Take a trader risking 2 percent of the current balance per trade who suffers ten consecutive losses. The balance is multiplied by 0.98 ten times, which is about 0.817, a drawdown of roughly 18 percent. The same streak at 10 percent risk per trade gives 0.9 to the tenth power, about 0.349, a 65 percent drawdown requiring a gain of more than 180 percent. Ten losses in a row sounds extreme, but with a strategy that wins 50 percent of the time, a run of that length is not impossible across a long career. If your edge is slimmer or your win rate lower, longer runs occur more readily. See losing streaks and revenge trading for the probabilities.
Risk per trade controls everything
| Risk per trade | Balance after 10 straight losses | Drawdown |
|---|---|---|
| 0.5% | 95.1% | 4.9% |
| 1% | 90.4% | 9.6% |
| 2% | 81.7% | 18.3% |
| 5% | 59.9% | 40.1% |
| 10% | 34.9% | 65.1% |
This is why position sizing is the one rule that matters most. You cannot control how many trades in a row lose, but you can control how much each one costs. Leverage makes it easy to take a position far larger than your risk rule allows; see lots, leverage and margin.
The psychological side
Drawdowns are not just numbers. As the account falls, traders tend to behave differently: they hesitate on valid setups, move stops, add to losers, or increase size to win it back. Each reaction deepens the hole. A shallow drawdown leaves your judgment intact; a deep one often does not. Having a rule for what to do at predefined drawdown levels removes the need to decide while stressed.
Drawdown rules you can write down
- Daily loss limit. For example, stop trading for the day after losing a fixed percentage.
- Weekly or monthly limit. After hitting it, take the remaining time for review rather than trading.
- Step-down rule. Halve position size after a drawdown of a set size, and return to normal only after recovering part of it.
- Review trigger. At a larger drawdown, stop and examine the journal: is this normal variance or a changed market?
Distinguishing variance from a broken strategy
Any strategy suffers a bad run now and then, but a drawdown much bigger than the worst in a fair backtest deserves scrutiny. If a test showed a maximum drawdown of 12 percent and live trading reaches 25 percent, either conditions changed, costs are higher than modelled, or the test was optimistic. A backtest's maximum drawdown is also a floor, not a ceiling: the worst is probably still ahead of the sample.
Recovery is geometric, not linear
One last point: percentage returns compound. Gaining 10 percent and then losing 10 percent leaves you down 1 percent (1.1 x 0.9 = 0.99). The more volatile the path, the more of your return is lost to this drag, even when the average return appears fine. Smooth, small-risk equity curves are not merely more comfortable; they compound better.
Takeaway
Treat avoiding large drawdowns as a primary goal, not a side effect. Keep risk per trade small enough that a long losing run is an irritation, not a catastrophe, and decide in advance what you will do when the account falls. The mathematics will not forgive an error on this point, and it will not negotiate.
Educational content only; not trading advice. Figures are illustrative arithmetic, not results.