How to Size a Bitcoin Trade
Combine balance, risk percent, and stop distance into one reliable formula.
Correct lot size ties together the dollars you're willing to lose, your stop-loss distance, and your broker's contract specs. The formula is simple: Lot = (Balance × Risk %) ÷ (Stop Distance × Contract). A $10,000 account, 1% risk ($100), and a $500 stop distance gives 0.2 BTC lots — a $12,968.8 position at today's ~$64,844.
Pros anchor to the "1% rule": never risk more than 1% of the account on a single trade. That way even 10 consecutive losses only draw the account down 10% — a statistically recoverable drawdown.
Leverage only changes the margin required, not the dollars at risk. A 0.2 lot BTC position at 10× leverage needs margin = position value ÷ 10. But when your stop hits, the loss is still $100.
Two mistakes wreck otherwise sound trades: (1) sizing off leverage instead of stop distance — a wider stop with the same lot means a bigger loss; (2) ignoring fees and funding on perpetuals. Round-trip taker fees on Binance/Bybit run 0.08-0.11% of position value; funding at 0.01% every 8h costs another 0.03%/day. On a $50k position that's $15+ per day just to hold.