Trading expectancy calculator
The single number that says whether a strategy makes money. Feed it your real numbers from your journal and it will tell you the truth, including how big a losing streak to expect.
The formula
expectancy = (win% × average win) − (loss% × average loss)
Positive means the strategy makes money over enough trades. Negative means it does not, and no amount of position sizing, discipline, or conviction changes that — sizing controls how fast you lose, not whether you lose.
Why win rate on its own is worthless
A 70% win rate sounds excellent and can still be a losing strategy, if the 30% of losses are four times the size of the wins. A 30% win rate sounds terrible and can be highly profitable at 1:4. Expectancy is the number that combines them, which is why it is the only one worth quoting.
The losing streak line matters more than it looks
At a 45% win rate, a run of ten losses in a row is entirely normal across a thousand trades. Traders who have not run that number abandon a working strategy during a streak, usually within two trades of the bottom. Knowing the streak to expect in advance is the difference between "this is normal" and "this is broken".
Get honest inputs
The output is only as good as the three numbers you feed it, and those are hard to estimate from memory. Pull them from a journal that contains every trade — the scratched ones, the revenge trades, and the ones you closed early out of nerves. Those are exactly the trades that move the average.
Fees are not a rounding error
At 40 trades a month, $3 of commission and slippage per trade is $1,440 a year. If your expectancy is $8 a trade, fees just took over a third of your income. Put a realistic number in that field.
Questions
What is trading expectancy?
The average amount you make or lose per trade, taking your win rate and the size of your wins and losses together. Positive expectancy means the strategy makes money over enough trades; negative means it does not, however good the last few trades felt.
What is a good expectancy?
Anything above zero after fees has an edge. What matters more is expectancy relative to risk: +0.2R per trade is a genuinely strong system, and most profitable retail traders sit between +0.05R and +0.3R.
How many trades do I need before the number means anything?
Around 100 trades gives you a rough signal and 300 gives you something you can lean on. Below 30 the number is mostly luck, in either direction.