Profit factor, expectancy and R-multiple, explained

Three numbers do most of the work in judging a trading strategy: the R multiple of each trade, the profit factor of the set, and the expectancy per trade. They are simple arithmetic, they are widely quoted, and they are misread constantly — usually by being read one at a time.

Here is what each one is, how to calculate it, what counts as good, and the specific way each can lie to you.

R multiple

R is the amount you risked on a trade. An R multiple expresses the result as a ratio of that risk rather than in currency.

Risk £100 and make £250, that is +2.5R. Risk £100 and get stopped out, that is −1R. Risk £100 and close early for £40, that is +0.4R.

Why bother

Currency results are not comparable. A £200 winner where you risked £50 and a £200 winner where you risked £800 are entirely different events, and averaging them produces a number that describes neither. R normalises for position size, so fifty trades become one honest distribution.

It also survives things that break currency-based records: growing the account, changing your risk per trade, or trading a different instrument. A +2R trade is a +2R trade at any account size.

How it misleads

R assumes your stop is real. If you routinely move stops, your recorded R is fiction — you did not risk 1R, you risked whatever you eventually allowed. This is the most common corruption of the metric and it always flatters. A losing trade you widened into a small winner records as +0.3R while actually having risked 2R.

Average R alone also hides shape. Two strategies can both average +0.3R: one grinds out +0.3R consistently, the other loses −1R eleven times and makes +4R four times. Same average, completely different experience, and only one of them is psychologically survivable.

Profit factor

Gross profit divided by gross loss, across a set of trades.

Above 1.0 you are making money. Below, you are not. The ratio tells you how much you win per unit lost, which makes it the quickest single read on whether a strategy is worth continuing.

What counts as good

• Under 1.0 — losing.
• 1.0 to 1.3 — marginal. Costs and slippage can eat this.
• 1.3 to 2.0 — a real, workable edge.
• Above 2.0 — strong, and worth checking the sample size before believing it.
• Above 4.0 on fewer than a hundred trades — almost always a small sample containing one enormous winner.

How it misleads

Profit factor is dominated by outliers. One exceptional trade can carry it for months, and a strategy whose edge lives in a single trade is one you will stop running before the next such trade arrives. Remove your largest winner and recalculate: if the figure collapses, you have one lucky trade, not an edge.

It also says nothing about the path. A profit factor of 2.0 achieved through a 40% drawdown is not the same business as 2.0 achieved smoothly, though the number is identical.

Expectancy

What you can expect to make, on average, per trade. Two equivalent forms:

With a 62% win rate, an average win of £190 and an average loss of £138:

Positive expectancy means the strategy makes money over enough trades. That is the whole test. Everything else — win rate, profit factor, how it feels — is commentary on how it gets there.

How it misleads

Expectancy is an average, and averages say nothing about order. A strategy with £65 expectancy can still deliver fifteen consecutive losers. The expectancy is not wrong; it just does not promise the sequence will be comfortable.

And it is only as good as the sample. Twenty trades tells you almost nothing. Expectancy computed on a handful of trades is a description of what happened, not a prediction of what will.

Why win rate is not on this list

Win rate is the most quoted figure in trading and, alone, close to meaningless. A 30% win rate is excellent if winners run at 4R and losers stop at 1R. An 80% win rate is a slow death if one loser erases nine winners.

Win rate only becomes informative next to average win and average loss — at which point you have expectancy, which already contains it. Treat a win rate quoted on its own, by anyone, as a claim with the important half missing.

Reading them together

None of the three is sufficient alone. Together they answer different questions:

• Expectancy — does this make money?
• Profit factor — how efficiently, per unit risked?
• R distribution — can I live through how it gets there?

A healthy set looks roughly like this:

Positive expectancy, a profit factor comfortably above 1.3, a positive average R, and a drawdown you could sit through. Any one of those figures in isolation would be a weaker statement than the six together.

How many trades before you believe any of it

More than you would like. A rough guide:

1. Under 30 — anecdote. Log them, do not conclude from them.
2. 30 to 100 — you can see obvious things. One setup clearly losing money, one session clearly worse. Not fine distinctions.
3. 100 to 300 — the metrics start to mean something, and you can compare subsets with some confidence.
4. 300+ — differences between similar setups become readable.

The mistake is not having too few trades. It is having few trades and acting as though you have many — changing a strategy after eight losses that were, statistically, entirely unremarkable.

Where they get genuinely useful

Computed across all your trades, these three tell you whether to carry on. Computed across subsets, they tell you what to change — and that is the difference between a statistic and a decision.

Split profit factor by setup and one is usually carrying the others. Split expectancy by session and the London and New York versions of “your strategy” are often different businesses. Split average R by whether you followed your plan, and the gap is frequently larger than the gap between your best and worst setup — which means the problem was never the strategy.

That requires the trades to carry those labels, which no broker statement provides. It is the argument in how to keep a forex trading journal, and the reason a journal beats a statement.

PipFlo computes all three on every trade and splits them by setup, session, pair, direction and plan adherence, which is the work these numbers are actually for. If you just want the arithmetic before a trade, the risk/reward calculator gives you the R and the breakeven win rate it implies, free and without an account.