Losses and gains are not symmetric. This is the brutal arithmetic every risk plan is built around.
Percentages compound from a smaller base after a loss: -10% needs +11%, -30% needs +43%, -50% needs +100%, -90% needs +900%. This asymmetry is the mathematical case for small per-trade risk — shallow drawdowns are cheap to repair, deep ones consume months of edge.
Mechanically anything under 100%; psychologically far less. Most professional programs treat 20-30% as the red line, beyond which required recovery demands unrealistic returns.
Fixed fractional risk per trade (0.5-2%), sizing from stops, cutting size after losing streaks — the position-size calculator implements the first two.
Even more: liquidation is a 100% drawdown of that margin. This math is why liquidation must never be the stop-loss.
Free, no signup, runs entirely in your browser. Educational tool — not financial advice. Practice the setup risk-free on the MarginPad paper-trading terminal before putting real money behind it.