Position size calculator
Decide what a wrong trade is allowed to cost, then let the stop distance decide the size. This is the calculation that keeps one bad entry from mattering.
Inputs
Result
size = (account x risk%) / |entry - stop|, and notional = size x entry.
The mistake this prevents
Sizing off leverage instead of off the stop. Leverage tells you what the venue allows; the stop distance tells you what the trade costs when it is wrong. Fees and slippage are on top, so treat the number as a ceiling rather than a target. See the complete worked process in crypto trading for beginners.