Profit factor is a trading strategy's gross profit divided by its gross loss over the same set of trades - one number that tells you whether the winners paid for the losers, and by how much. If a strategy's winning trades made $1,500 in total and its losing trades lost $1,000 in total, its profit factor is 1,500 / 1,000 = 1.5: every dollar lost was matched by a dollar and a half won. A profit factor above 1 means the strategy made money over those trades, exactly 1 means it broke even, and below 1 means it lost. Because it is a simple ratio, profit factor is one of the most common numbers in backtest reports - MetaTrader's Strategy Tester shows it on every run - and one of the easiest to over-trust. It says nothing about how many trades produced it, how large the drawdowns were along the way, or whether trading costs were included, so it is best read next to expectancy, drawdown and trade count rather than on its own.
The formula
Profit factor is gross profit divided by gross loss, both taken as positive amounts:
profit factor = sum of all winning trades ÷ sum of all losing trades
The same number can be written from win rate and average trade size, which makes it easier to see what drives it: profit factor = (win rate × average win) ÷ (loss rate × average loss).
Profit factor at different win rates
The table below uses the same combinations as the expectancy article, with average loss fixed at 1R. Every value is plain arithmetic from the formula above.
| Win rate | Average win (R) | Profit factor | Expectancy per trade |
|---|---|---|---|
| 30% | 3 | 1.29 | +0.20R |
| 40% | 2 | 1.33 | +0.20R |
| 60% | 1 | 1.50 | +0.20R |
| 50% | 1 | 1.00 | 0.00R |
| 70% | 0.25 | 0.58 | −0.125R |
The first three rows earn exactly the same amount per trade, yet show three different profit factors. Profit factor and expectancy measure different things - one is a ratio of totals, the other an average per trade - which is why reading only one of them hides part of the picture.
What counts as a good profit factor
No single profit factor is "good" in isolation, because the same value means different things depending on the sample and the costs behind it. A value only slightly above 1 leaves very little room: spread, commission and slippage that a backtest under-models can turn it into a loser in live trading (see how the spread raises your break-even point). A very high value is not automatically better either - it often comes from few trades, or from rules tuned until the losers disappeared, which is the classic sign of curve fitting.
Three ways profit factor misleads
Profit factor is easy to distort, and most of the distortions push it upward.
- Small samples. With a handful of trades, one large winner can carry the whole ratio. The fewer trades behind the number, the less it tells you.
- Very few or no losing trades. If gross loss is tiny, the ratio becomes huge; with zero losing trades it cannot be calculated at all. That is a reason to look harder, not a sign of a perfect strategy.
- Costs left out. A profit factor calculated before spread and commission describes a strategy you cannot actually trade. Make sure the backtest charges realistic costs.
How to use it in practice
Use profit factor as a quick filter, then confirm with the numbers it leaves out. Check how many trades produced it, what the maximum drawdown was, what the expectancy per trade is, and whether the value holds up on a period the strategy was not tuned on. AlgoPuzzle's Strategy of the Week listings show profit factor next to return, drawdown and the test window for exactly this reason - one ratio alone is not a verdict.
AlgoPuzzle is a no-code strategy builder: you assemble entry and exit rules from blocks, and its built-in backtester shows profit factor alongside the rest of the statistics from a quick simulation on 1-minute MetaTrader 5 data. Export a MetaTrader 5, MetaTrader 4 or cTrader file and confirm those numbers in the platform's own tester before going live.
Common questions
What is profit factor in trading?
Profit factor is a strategy's gross profit divided by its gross loss over the same set of trades. A profit factor above 1 means the winning trades made more than the losing trades lost; below 1 means the strategy lost money overall; exactly 1 means it broke even.
What is a good profit factor?
There is no universal threshold, because profit factor depends on how many trades it is based on and whether costs are included. As a rule of thumb, anything barely above 1 leaves little room for spread, commission and slippage, and any very high value on a small number of trades deserves suspicion rather than celebration.
How is profit factor different from expectancy?
Expectancy is the average result per trade, measured in money or in R. Profit factor is a ratio of total wins to total losses. Two strategies can have the same expectancy and different profit factors, so the two numbers answer different questions and are best read together.
Can profit factor be misleading?
Yes. On a small sample one large winning trade can push it far above 1, a backtest with almost no losing trades produces a huge or undefined value, and a figure calculated before trading costs can look healthy while the same trades lose money after costs.