Position Size Calculator — Size Any Trade to a Fixed Risk

Tools / Position Size Calculator

Position Size Calculator

Account size, risk %, entry and stop — exactly how many units to trade so a loss only costs your pre-decided slice of the account. Runs entirely in your browser.

HOW TO USE IT
  1. Enter the symbol (optional) — it simply labels the result so you can keep track when sizing several ideas.
  2. Enter your account size. Use the balance you actually trade with, not your total net worth.
  3. Set your risk per trade as a percentage. Many traders use 0.5–2%. This is the single most important number on this page: it decides how much of the account one losing trade can cost you.
  4. Enter your planned entry price.
  5. Enter your stop-loss price — the level that proves the idea wrong, placed where the structure breaks (beyond the swing extreme), not at a round number that feels comfortable.
  6. Read your position size. The tool converts your risk into units: risk amount ÷ distance between entry and stop. A wider stop returns a smaller size, so your risk stays identical either way.
Why this matters. Sizing by a fixed percentage means every trade risks the same amount whatever the stop distance — which is what stops one bad trade doing disproportionate damage. Decide the stop from the chart first, then let the size follow. Never widen a stop to justify a bigger position. Pair it with the risk-of-ruin calculator to see what your chosen risk % does over many trades.
Educational tool — not financial advice. Prefer it automated? FibScanner applies these levels across 293 markets for you.