Minimum win rate calculator
The minimum win rate is what zeroes expected result: (1 + cost) ÷ (1 + reward/risk). With reward equal to risk and zero cost it is 50%; with a cost of 10% of risk it rises to 55%. With reward at twice the risk, 33% is enough without cost — and expectancy at a 45% win rate is +0.35R.
Enter the reward/risk ratio, the cost per trade as a percentage of risk and, optionally, your real win rate. The calculator returns the minimum rate to break even and the expectancy per trade in multiples of risk.
To go deeper into each part of this calculation: Expectancy · Risk-reward ratio · Spread
What this calculator solves
Every strategy is a combination of three numbers: how much it makes when it wins, how much it loses when it loses and how often it wins. Two of them define the third. This calculator answers what win rate a reward/risk ratio demands — and why cost changes the answer.
It is the calculation that dismantles the idea that 'winning more than half' is enough: with a target smaller than the stop, a 60% win rate can be a guaranteed loss.
How the calculation works
Expectancy per trade, in R (multiples of risk): p × b − (1 − p) × 1 − c, where p is the win rate, b the reward/risk ratio and c the cost per trade as a fraction of risk.
Setting expectancy to zero and solving for p: minimum p = (1 + c) ÷ (1 + b). Cost sits in the numerator because it is paid on every trade, win or lose.
Cost as a fraction of risk: if you risk 100 per trade and pay 10 in spread plus commission, c = 0.10. With a tight stop that number grows fast — it is why scalping demands such a high win rate.
Full example
2:1 ratio, cost of 10% of risk. Minimum rate: (1 + 0.10) ÷ (1 + 2) = 36.7%. At a real 45%: 0.45 × 2 − 0.55 − 0.10 = +0.25R per trade. Over 100 trades risking 100 each, that is 2,500 expected.
0.5:1 ratio (target smaller than stop), zero cost. Minimum rate: 1 ÷ 1.5 = 66.7%. A strategy with a 60% win rate and that target loses money by definition, before any cost.
After the calculation
Real win rate and reward/risk come from the journal, not from memory. TCC computes both from recorded trades, alongside expectancy and profit factor — the numbers that say whether the strategy holds up.
FAQ
What is expectancy in R?
The average expected result per trade, measured in multiples of risk. +0.25R with a 100 risk is 25 per trade, averaged over many trades.
Why does cost raise the minimum rate?
Because it is paid on every trade, win or lose. Every 10% of risk in cost adds 10 points to the formula's numerator.
Create a free account and measure the real rate in the journal