PRAETIR / Metrics

Calculate maximum drawdown correctly

Maximum drawdown is the largest decline in an equity series from a previous peak to a subsequent trough. Trade sequence and the definition of equity are essential.

Track each new peak

Begin with initial equity and process trades in their actual sequence. After each result, compare new equity with the previous maximum. The difference from that peak is current absolute drawdown; the largest difference is maximum drawdown.

Our example begins at USD 10,000, reaches USD 10,285 after trade three and later ends at USD 10,110. The largest decline is USD 175, or approximately 1.70 percent of the corresponding peak. The overall series is still positive.

Closed trades versus intratrade risk

Our example uses closed trades after costs. It excludes unrealized losses between closes. A broker or prop firm may instead use equity including open positions or a particular trailing rule. These definitions are not interchangeable.

Account for deposits and withdrawals

A withdrawal is not a trading loss. Adjust the equity series for external cash flows or use a properly defined return series. Document the period and cost basis. A small historical drawdown does not cap potential future losses.

Formula

Drawdown(t) = running equity peak − current equity(t)

A reproducible example

Synthetic dataset · 8 NQ trades · USD · Timestamps in UTC
The same eight trades — before and after costs
MeasureBefore costsAfter costs
Sum of winning trades (USD)550.00530.00
Absolute sum of losing trades (USD)400.00420.00
Balance: wins minus losses (USD)150.00110.00
Profit Factor1.3751.262

USD 550 in wins − USD 400 in losses = USD 150 balance before costs. After 8 × USD 5 in costs, USD 110 remains. Net profit factor first deducts costs from each trade: 530 / 420 ≈ 1.262.

Balance before costs
150.00 USD
Total costs
40.00 USD
Balance after costs
110.00 USD
Profit factor after costs
1.26
Expectancy per trade
13.75 USD
Max. drawdown
175.00 USD

Equity after closed trades; synthetic starting equity: USD 10,000.

TradeEquity (USD)Drawdown (USD)
010,000.000.00
110,145.000.00
210,040.00105.00
310,285.000.00
410,130.00155.00
510,175.00110.00
610,120.00165.00
710,215.0070.00
810,110.00175.00

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