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Trading Expectancy Calculator

Expectancy combines how often a system wins with how much it wins and loses. A high win rate can still lose money, and a low win rate can remain profitable when the payoff distribution is strong enough.

Observed strategy outcomes

Use realized out-of-sample averages after costs where possible.

Expected distribution

Positive model

Net expectancy / trade

0.21R

Expected over 100 trades

21R

Breakeven win rate

35.71%

Profit factor proxy

1.47

This is the average of a modeled distribution, not the path the next 100 trades will take. Sampling error, dependence and regime change can dominate a small backtest.

Formula and assumptions

Expectancy

(Win rate × average win) − (Loss rate × average loss)

Expected R per trade before costs, assuming the inputs represent the future distribution.

Sample expectation

Expectancy × number of trades

The mathematical average over a sample, not a guaranteed path.

Profit factor proxy

(Win rate × avg win) ÷ (Loss rate × avg loss)

Gross expected wins divided by gross expected losses.

Breakeven win rate

Avg loss ÷ (Avg win + avg loss)

Minimum hit rate before trading costs at the entered payoff values.

How to use the result

  1. 01

    Use out-of-sample trades

    Inputs taken from the same period used to design a strategy are optimistic. Reserve unseen data or forward trades for estimation.

  2. 02

    Use averages, not the largest winner

    One outlier can dominate a small sample. Report mean, median, dispersion and the number of observations together.

  3. 03

    Model costs honestly

    Subtract fees, spread, slippage and funding from trade results before calculating average win and loss.

  4. 04

    Expect a distribution

    Positive expectancy does not imply a smooth equity curve. Losing streaks and drawdowns remain normal outcomes.

What the number can get wrong

  • Estimating expectancy from a handful of trades or only the best market regime.
  • Entering the planned target R instead of the average R actually realized.
  • Ignoring losses from rejected fills, slippage and strategy execution differences.
  • Treating expected sample profit as a forecast of the next sample path.

Questions

What is positive trading expectancy?+

Expectancy above zero means the average modeled trade earns more than it loses over many repetitions. Statistical uncertainty and costs still determine whether the observed edge is credible.

Can a 40% win-rate strategy be profitable?+

Yes. With an average win of 2R and an average loss of 1R, expectancy is 0.2R per trade before costs: 0.4 × 2 − 0.6 × 1.

How many trades are needed to trust expectancy?+

There is no universal cutoff. More observations across different regimes improve confidence, but dependence, parameter selection and changing market conditions can still make a large backtest misleading.

Move the calculation onto the chart

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Updated 2026-08-26 · Estimates depend on the inputs and assumptions shown. Educational use only, not financial advice.