Win rate confidence calculator
A measured win rate is an estimate, and the fewer trades behind it the wider the range it could really be. This calculator gives the 95% range for your true win rate from your trades and winners, compares it with the break-even for your reward to risk, and says how many trades it takes for an edge that size to show.
Last updated 30 September 2026.
A 95% interval. Your measured win rate is one draw from it.
If your real win rate is the one you measured, this is roughly how many trades it takes for the evidence to be convincing.
How to read it
- If the whole range sits above break-even, the evidence says you have an edge.
- If break-even falls inside the range, you cannot tell yet. That is the most common result, and it is not bad news; it is a sample size.
- If the whole range sits below break-even, the evidence says the system loses.
Why 60 trades is rarely enough
Twenty-seven wins from sixty trades is 45%. At a reward of 2 to 1 the break-even is 33.3%, so it looks comfortably ahead. But the range those sixty trades support is wide enough to include win rates near break-even, and a run of good fortune produces the same record. The calculator's last line is how many trades it would take to settle it.
STS Trading applies the same idea to every setup it shows: any record under 30 trades is marked as thin and never graded as a strong edge.
A calculator shows what follows from the numbers you enter. It is not a forecast and not personal financial advice. Trading carries risk and you can lose money.
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