Position size is the number of contracts, shares, or coins held in a trade. The professional way to set it is to back into it from a fixed risk budget: pick the % of equity to risk on this trade, pick a stop distance, and let the position size fall out as risk-budget ÷ stop-distance.
Fixed-fraction sizing (always risk 1% of equity) gives a position size that scales with the account, so winning streaks compound and losing streaks shrink risk automatically. Fixed-lot sizing (always trade 1 BTC) does not.
Position size is not the same as leverage. You can be 1x leveraged and still oversize a position by setting the stop too far from entry. The right framing is always 'how many dollars do I lose if my stop hits?'
Formula
size = (equity · risk_pct) / |entry_price − stop_price|
Example
Equity = 10,000 USDT, risk_pct = 1%, entry = 50,000, stop = 49,500. Size = (10,000 · 0.01) / 500 = 0.2 BTC.
How Noon Barbari uses Position size
Every concept here is implemented in the platform. Open the relevant docs or tool to see it in action.
Position size calculator →Related terms
- Risk
Risk per trade
Dollar amount (or % of equity) you lose if the stop on a single trade hits.
- Risk
Stop loss
A pre-committed exit level that caps the maximum loss on a trade.
- Risk
Leverage
Position notional divided by posted margin. 10× leverage = 10× the equity exposure.
- Risk
Risk-reward ratio
Ratio of potential gain to potential loss on a trade — also written R-multiple.