Free Tools

Position Size Calculator

Size every trade so a single loss never costs more than you decided. Enter your account, risk %, entry, and stop — get the exact position size.

Fill in account size, risk %, entry and stop to size your position.

Free, no signup. Not financial advice. Results are estimates — verify against your exchange.

How it works

Risk-first sizing

Instead of guessing how much to buy, you fix how much you are willing to lose (e.g. 1% of the account) and let the stop distance determine the size. This keeps risk constant regardless of the coin or volatility.

The math

Amount risked = account × risk%. Position size (units) = amount risked ÷ |entry − stop|. Position value = size × entry. With leverage, required margin = value ÷ leverage.

Assumptions

  • · Risk % is the share of your account you are willing to lose if the stop-loss is hit.
  • · Pick an exchange and pair to set the currency labels (base/quote) — this changes labels only, not the math.
  • · Enter your own fee per leg (defaults to 0.05%); the size then accounts for round-trip cost. Slippage is not modelled.
  • · Position size is in base units (e.g. BTC or shares); value and margin are in the pair’s quote currency.

FAQ

How much should I risk per trade?+

Most disciplined traders risk 0.5–2% of their account per trade. At 1%, it takes a long, sustained losing streak to do serious damage — which is the point of fixed fractional risk.

How is position size calculated from a stop-loss?+

Position size (in units) = (account × risk%) ÷ the distance between entry and stop price. A tighter stop allows a larger position for the same dollar risk; a wider stop means a smaller position.

Does leverage change my risk?+

Leverage changes the margin required, not the dollar risk — that is set by your stop distance and size. But higher leverage moves your liquidation price closer, so keep the stop well inside it.