Maximum Drawdown (MDD) Calculator

Understanding the maximum drawdown calculator — concept and principle

Maximum drawdown (MDD) is the largest percentage fall from a peak to a later low in a series of portfolio values. It measures the worst loss an investor would have suffered by buying at the top and holding through the bottom. Enter values in time order (daily, monthly or yearly) to see the MDD, where it happened, the gain needed to recover and the total return from first to last value.

How it is calculated

The calculator walks through the series and keeps a running peak, the highest value seen so far.

• Drawdown at each point: (value − running peak) ÷ running peak.
• Maximum drawdown: the most negative of these drawdowns, with the peak and trough that produced it.
• Gain needed to recover: 1 ÷ (1 + MDD) − 1.
• Total return: last value ÷ first value − 1.

Values must be positive; at least two are needed.

The principle

Volatility treats ups and downs alike, but investors feel losses from a high point most. MDD captures exactly that path-dependent pain: it depends on the order of returns, not only their size. Because a loss shrinks the base, recovering from a drawdown requires a larger percentage gain than the drop itself. MDD is also the basis of ratios such as the Calmar ratio (annual return ÷ maximum drawdown).

Worked example

Default series: 100, 120, 110, 140, 98, 105, 150, 135.

1. Running peaks: 100, 120, 120, 140, 140, 140, 150, 150.
2. Largest drop: from 140 (point #4) to 98 (point #5): (98 − 140) ÷ 140 = −30%.
3. Gain needed to recover: 1 ÷ 0.70 − 1 = 42.9%.
4. Total return: 135 ÷ 100 − 1 = 35%.

The later fall from 150 to 135 is only −10%, so it does not change the MDD.

How to read the result

A diversified stock portfolio can see drawdowns of 30–50% in a severe bear market, while a cautious bond-heavy mix usually falls far less. Compare MDD with your tolerance: if a −30% drop would make you sell, the strategy is too risky for you. MDD from a short or calm period understates the risk, and monthly data hides intramonth lows, so daily data generally shows a deeper MDD.

Common mistakes

• Measuring from the first value instead of from the running peak.
• Mixing data frequencies, or including deposits and withdrawals in the values.
• Reading a past MDD as the worst that can ever happen.
• Forgetting that a strong total return can still hide a painful drawdown.

Frequently asked questions

Is maximum drawdown the same as volatility?

No. Volatility measures the spread of returns; MDD measures the single worst peak-to-trough loss.

Should I use prices or total-return values?

Total-return values including dividends give a fairer picture of an investor's experience.

What is a drawdown duration?

The time from a peak until the value regains that peak, which can matter as much as the depth.

Sources: Magdon-Ismail, M. and Atiya, A., "Maximum Drawdown", Risk Magazine (2004) · Bacon, C., Practical Portfolio Performance Measurement and Attribution