Profit Factor
Profit factor is the ratio of gross profit to gross loss over a given period. It is one of the most useful single-number summaries of a trading strategy's quality.
Profit factor is calculated by dividing total gross profit by total gross loss:
Profit Factor = Gross Profit ÷ Gross Loss
A profit factor of 1.0 means you break even. Above 1.0 means you’re profitable. Below 1.0 means you’re losing money overall.
What’s a good profit factor?
| Profit Factor | Interpretation |
|---|---|
| Below 1.0 | Losing strategy |
| 1.0 – 1.25 | Marginal: likely not surviving commissions long-term |
| 1.25 – 1.75 | Solid: a real edge |
| 1.75 – 2.5 | Strong: consistently profitable |
| Above 2.5 | Elite: or overfitted to historical data |
These thresholds assume a reasonable trade sample size (50+ trades). With fewer trades, profit factor is not a reliable metric.
Why profit factor beats win rate
A 70% win rate sounds impressive: but if your average winner is $100 and your average loser is $400, your profit factor is approximately 0.58 and you’re losing money.
Profit factor combines both win rate and average R:R into one number. It’s harder to fool yourself with profit factor than with win rate alone.
Profit factor across trade segments
Where profit factor becomes most useful is when you calculate it across subsets of your trades: not just your overall history.
Your A-setup might have a profit factor of 2.4. Your out-of-plan trades might be 0.6. If you only look at your overall number, that 0.6 is dragging down the 2.4 and hiding what’s actually working.
This is why filtering your journal by setup tag, instrument, time of day, or rule compliance status: and calculating profit factor on each segment: is more valuable than your headline number.
Profit factor and sample size
Profit factor is unreliable with fewer than ~50 trades. With 10 trades, a single outlier win can take your profit factor from 0.8 to 4.0. The number becomes meaningful as sample size grows.
As a rule of thumb: don’t make major strategy decisions based on profit factor until you have at least 30–50 trades in the segment you’re evaluating.
Related metrics
- Win rate: the percentage of trades that close positive
- Expectancy: average profit per trade in dollar terms
- Average R:R: the ratio of average winner to average loser