What Is Profit Factor?
Profit factor is total gross profit divided by total gross loss. A value of 1.6 means the strategy earned $1.60 for every $1.00 it lost. Below 1.0 the strategy loses money, and unusually high values almost always indicate a short sample rather than a strong edge.
What is the formula?
Profit factor = sum of all winning trades ÷ absolute sum of all losing trades.
Worked example. 120 trades produce $84,000 of gross profit and $52,500 of gross loss. Profit factor = 84,000 ÷ 52,500 = 1.60. Net profit is $31,500, which is a different and less comparable number because it depends on how many trades were taken.
It can also be built from win rate and payoff ratio: profit factor = (W × average win) ÷ (L × average loss). At a 40% win rate and a 2.5:1 payoff that is (0.4 × 2.5) ÷ (0.6 × 1.0) = 1.0 ÷ 0.6 = 1.67.
What is a good profit factor?
Above 1.0 is profitable by definition. Systems that persist over long periods commonly sit somewhere between roughly 1.2 and 1.8 after realistic costs. Values above 3 are usually one of three things: a small sample, a period that suited the strategy, or costs that have not been subtracted.
The reason is arithmetic. A profit factor of 3 at a 50% win rate implies an average win three times the average loss, sustained. That combination exists; it is rare, and it is rarer still in the sample sizes these numbers are usually quoted from.
What does it hide?
The distribution. One enormous winner can carry a profit factor on its own. Recompute it with the single best trade removed: if 1.60 becomes 0.95, the strategy is one lucky trade, not an edge.
Drawdown. Profit factor is path-independent. Two strategies with identical profit factors can differ enormously in how deep a hole they dug on the way.
Trade count. A profit factor of 2.4 over 15 trades and one of 1.4 over 900 are not comparable claims.
Costs. $12 per round turn on 120 trades is $1,440 — which moves the example above from 1.60 to 84,000 ÷ 53,940 = 1.56, and moves a marginal system across the line entirely.
How does this connect to a track record?
Treat a very high profit factor from a tested strategy with the same suspicion as a very high backtested Sharpe. Overfitting a backtest is easy after only a modest number of configurations, and the probability of it rises with each one tried.[1] A profit factor above about 2 on a fitted history usually says more about the search than the edge.
The published literature holds itself to a stricter bar than that: Harvey, Liu and Zhu argued that so many predictors had been tested in finance that a new claim should clear a t-statistic above 3.0 rather than 2.0.[2] A fitted history inflates the same way a survivors-only average does — the versions that failed were discarded before you saw the number, exactly as closed funds are missing from a performance average.[3]
A metric is a summary of a record, so it inherits every weakness of that record. Computed from trades selected after the fact, it is a number about the selection. kappi commits each trade before it resolves and publishes it on a Merkle-anchored log, so PnL, RME, correlation to SPX, mean R:R and trade count over 30, 100 and 200-day windows are computed over everything that was committed, losses included. $15/month to keep a record; reading one is free.
Sources
- Bailey, Borwein, López de Prado & Zhu, 'Pseudo-Mathematics and Financial Charlatanism: The Effects of Backtest Overfitting on Out-of-Sample Performance', Notices of the AMS 61(5), 2014, 458 read 2026-08-16
- Harvey, Liu & Zhu, '… and the Cross-Section of Expected Returns', Review of Financial Studies 29(1), 2016, 5–68 — argues a newly claimed factor should clear a t-statistic above 3.0 read 2026-08-16
- Brown, Goetzmann, Ibbotson & Ross, 'Survivorship Bias in Performance Studies', Review of Financial Studies 5(4), 1992, 553–580 read 2026-08-16
Frequently asked questions
What is a good profit factor?
Anything above 1.0 is profitable. Strategies that persist commonly sit between roughly 1.2 and 1.8 after costs. Values above 3 usually indicate a small sample or omitted costs.
How do you calculate profit factor?
Divide the sum of all winning trades by the absolute sum of all losing trades. $84,000 of gross profit against $52,500 of gross loss is a profit factor of 1.60.
What does profit factor hide?
The distribution of trades, the depth of drawdown, and the sample size. Recompute it without the single largest winner — if it falls below 1.0, the result rests on one trade.
How does profit factor relate to win rate?
Profit factor = (win rate × average win) ÷ (loss rate × average loss). A 40% win rate at a 2.5:1 payoff gives 1.0 ÷ 0.6 = 1.67.