What goes into the model
Enter the average positive trade before costs, the absolute average negative trade before costs and equal round-trip costs per trade. All inputs need the same currency and position basis. The model contains only these two gross outcome types.
Do not deduct the same fees again from averages already calculated after costs. If fees differ between groups, calculate their net outcomes first; this simplified input model assumes equal costs.
Why 40% is insufficient here
With an average gross win of USD 150 and an average gross loss of USD 100, the threshold before costs is 40%. With USD 5 in costs, a win becomes USD 145 and a loss becomes USD 105. The threshold rises to 105 / 250 = 42%.
For 100 synthetic trades, 42 × 145 − 58 × 105 = USD 0. This is model arithmetic, not an estimate of the win rate you will achieve.
When gross winners no longer make money
If costs exceed the average gross win, break-even is unattainable in this two-outcome model. If they are exactly equal, 100% gross winners are required merely to reach zero. The calculator identifies these cases explicitly.
Compare against your journal
Calculate inputs from a complete sequence. A high win rate can still produce a negative result when wins are small and losses are large. Read the threshold alongside expectancy, drawdown, trade count and the actual distribution of costs.
Break-even rate = (gross loss + costs) / (gross win + gross loss)