Maximum Drawdown Explained: Measuring Worst-Case Loss

Maximum drawdown is the largest percentage drop from a portfolio's peak value to its lowest point before a new peak is reached. It captures the worst loss an investor would have endured buying at the top and selling at the bottom, making it a direct measure of downside risk and capital preservation.

What is maximum drawdown?

Maximum drawdown (MDD) is the largest peak-to-trough decline a portfolio experiences over a given period, quoted as a percentage of the peak value. It answers a blunt, practical question: across this stretch of history, what was the worst hit to my capital from a high point to the low that followed? Because it focuses on the single deepest loss, it is one of the clearest gauges of downside risk.

What makes MDD valuable is that it reflects lived experience rather than an abstract average. An investor does not feel standard deviation; they feel watching a portfolio fall from its high and wondering whether to sell. That emotional pressure is exactly when discipline breaks down, which is why maximum drawdown belongs alongside the Sharpe ratio and the limits set in trading risk management when judging any strategy.

What is the maximum drawdown formula?

The maximum drawdown formula compares the lowest point after a peak to that peak. It is:

Maximum Drawdown = (Trough Value - Peak Value) / Peak Value

Peak Value  = the highest portfolio value recorded so far
Trough Value = the lowest value that follows that peak before a new high

The result is negative or written as a positive percentage of loss. The two inputs are specific. The peak is the running maximum value the portfolio has reached. The trough is the lowest value that occurs after that peak and before the portfolio climbs to a new high. You scan the entire equity curve, measure every peak-to-trough fall, and the largest of those falls is the maximum drawdown. Multiply by 100 to express it as a percentage.

How do you calculate maximum drawdown? (worked example)

Calculating maximum drawdown means finding the biggest drop from any high to the lowest point that follows it. Take an illustrative portfolio whose value over six periods runs: 100, 130, 90, 110, 70, 120 (in thousands).

The highest peak is 130 at period 2. The lowest value that follows it is 70 at period 5. Plugging into the formula: (70 - 130) / 130 = -60 / 130 = -46.2%. That is the maximum drawdown. Note that the trough is measured against the prior peak, not against the starting value, and a later partial recovery does not change the maximum drawdown already recorded.

Why does maximum drawdown matter more than volatility?

Maximum drawdown matters because it measures the actual worst-case loss in capital, the path that determines whether an investor survives a strategy or abandons it. Volatility, by contrast, averages swings in both directions and treats a sharp gain the same as a sharp loss. Drawdown ignores the upside and zeroes in on the downside journey that hurts.

The deeper reason is the math of recovery. Losses and the gains needed to undo them are not symmetric. A 20% drawdown needs a 25% gain to break even, a 50% drawdown needs a 100% gain, and an 80% drawdown needs a 400% gain just to return to the starting point. The table below shows why deep drawdowns are so dangerous: each extra percentage of loss demands disproportionately more to recover.

What is a good maximum drawdown?

There is no universal threshold for a good maximum drawdown, but smaller is always better because it means less capital was destroyed at the worst point. What counts as acceptable depends on the asset class, the strategy, and your own tolerance. A broad stock index can fall 40% to 50% in a severe bear market, while a conservative bond-heavy allocation might cap losses far lower.

The right way to read MDD is relative and personal. Compare a strategy's drawdown to a relevant benchmark over the same window, since a 30% drawdown is reasonable if the benchmark fell 35% but alarming if it fell only 10%. Then weigh it against your own staying power: the worst drawdown you can tolerate without selling at the bottom is the real constraint, because a strategy you abandon at its trough delivers none of its long-run return.

How does maximum drawdown work with recovery time?

Recovery time, also called the drawdown duration or time to recovery, is how long a portfolio takes to climb from its trough back to its previous peak. Maximum drawdown tells you how deep the hole was; recovery time tells you how long you sat in it. Both matter, because a shallow loss that lingers for years can be as discouraging as a sharp one that bounces back fast.

Together, depth and duration describe the full shape of the pain. Two strategies can share the same maximum drawdown yet differ enormously in how long they keep an investor underwater. This is why serious performance reviews report drawdown depth and duration side by side, and why pairing MDD with the Sharpe ratio gives a fuller picture than either alone, as covered in the cluster pillar on portfolio management.

Putting maximum drawdown in context

Maximum drawdown is the reality check that return figures and Sharpe ratios can hide: the single worst loss an investor would actually have lived through. Because recovery math is unforgiving and human discipline is fragile, controlling drawdown is often more important than maximizing return. Use it to stress-test any strategy, compare it against a benchmark and your own tolerance, and treat a manageable drawdown as the foundation that lets compounding do its work over time.