What Is Profit Factor? (Trading Metric Explained)

Profit factor is the total money a strategy made on its winning trades divided by the total it lost on its losing trades. Above 1 is profitable; below 1 loses money.

Profit factor = gross profit / gross loss (as a positive number).

Add up the gains from every winning trade. Add up the losses from every losing trade. Divide the first by the second. A profit factor of 1.5 means the strategy made $1.50 for every $1.00 it lost.

Imagine ten trades. The winners made $400, $300, $200, $100, and $100 - gross profit of $1,100. The losers dropped $200, $200, $150, and $100 - gross loss of $650.

Profit factor = 1,100 / 650 ≈ 1.69. For every dollar the strategy lost, it made about $1.69. That's a respectable figure - but notice it rests heavily on that single $400 win.

Profit factor folds win rate and trade size into one number. A strategy can win only 40% of the time and still have a great profit factor if its wins are much bigger than its losses - which is why win rate alone is a poor measure.

It's a fast way to compare strategies on the same footing, and a quick sanity check: a profit factor only barely above 1 leaves no margin once real-world fees and slippage are taken out.

How profit factor can mislead:

• Trusting it on too few trades. A profit factor from five trades is noise; one lucky winner can dominate it.
• Ignoring concentration. If a single outlier trade supplies most of the gross profit, the figure won't hold up live.
• Forgetting costs. A backtest that omits fees and slippage inflates gross profit and shrinks gross loss, overstating the profit factor.
• Reading it without drawdown. A high profit factor can still come with a painful equity dip along the way.