Trade Sample Size Planner

Six-step workflow

1. Copy current values from the official account, platform, or journal.
2. Keep every unit consistent; do not mix ticks, points, pips, dollars, or percentages.
3. Enter the planning assumptions without changing them to force a preferred answer.
4. Calculate and read every output, including the warning below the headline number.
5. Verify instrument specifications and binding firm rules at the official source.
6. Save the result with its date and compare it with what actually happened.

Understand the output

Formula: Approximate proportion sample = z² × p × (1 − p) ÷ margin².

Worked example: At 95% confidence, 50% expected win rate, and ±10-point margin, the simple estimate is 97 trades. Eight qualifying trades per week take about 12 weeks.

Common mistakes: choosing margin after results, treating dependent trades as independent, ignoring market regimes, and stopping early after a streak.