Profit Factor

Last updated: May 20, 2026

Total winnings divided by total losings. The trading-system sanity check.

Quick Answer

What is Profit Factor?

Profit factor is the ratio of gross profits to gross losses across all trades or periods. A profit factor of 2.0 means the portfolio earned $2 in winning trades for every $1 it lost in losing trades. Below 1.0 means losses exceeded gains overall. Widely used in trading-system evaluation.

PF = Σ Rᵢ (where Rᵢ > 0) / |Σ Rᵢ (where Rᵢ < 0)|

Formula

PF = Σ R_i (where R_i > 0) / |Σ R_i (where R_i < 0)|

Sum (not average) of all positive returns divided by absolute sum of all negative returns.

Unlike gain/loss ratio (which averages), profit factor sums — so it counts both frequency and magnitude of wins.

Intuition — what is this number telling you?

Profit factor is the canonical trading-system evaluation metric. Profitable systems typically run between 1.3 and 2.5; values above 3.0 in a backtest often indicate overfitting and rarely survive live trading. A backtest with profit factor of 5 is almost certainly broken.

Worked example

Step-by-step

Sum of all gains in winning periods: $48,500. Sum of all losses in losing periods: −$22,000.

PF = 48,500 / 22,000 = 2.20

For every dollar lost, the strategy earned $2.20 — solidly profitable.

What's a good Profit Factor value?

Profit factor by quality:

PF	Verdict
< 1.0	Losing strategy.
1.0 – 1.3	Marginal — barely covering costs in practice.
1.3 – 2.0	Profitable. Realistic for live systems.
2.0 – 3.0	Strong system.
> 3.0	Suspicious in a backtest. Often overfit.

Frequently asked questions about Profit Factor

Why are very high profit factors suspicious?

Because real markets are noisy. Anything above 3.0 in a backtest is usually the result of curve-fitting parameters to the in-sample data. Live trading rarely reproduces it.

How is profit factor different from gain/loss ratio?

Profit factor sums all wins and losses. Gain/loss ratio averages them. Profit factor accounts for the frequency of wins; gain/loss ratio does not.

What profit factor should I aim for?

1.5–2.0 in a live strategy is solid. Anything below 1.3 is marginal once you account for costs.

Does Foliolytic compute profit factor?

Yes — alongside win rate and gain/loss ratio in the timing section.

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