Position size calculator
This answers one question: if a losing trade is only allowed to cost a fixed share of the account, how large can the position be? It is the arithmetic that most blown accounts skipped.
How the number is produced
The risk budget is the account size multiplied by the risk percentage. The risk per unit is the distance between the entry price and the stop price. Dividing the first by the second gives the position size in units; multiplying that by the entry price gives the notional value. Dividing the notional by the account size gives the leverage the position implies.
Nothing is sent anywhere. There is no account, no tracking of what you type, and the calculation happens in your browser.
What it deliberately does not do
It does not include trading fees, funding on perpetual contracts, or slippage — all three make the real loss larger than the budgeted one. It does not model an exchange's maintenance-margin or liquidation logic, so it is not a liquidation estimator. It does not know your instrument's contract size, so round the result down to what your venue accepts, never up.
Most importantly, it is not advice to take any trade. See our risk disclosure and how fees work, since fees and funding are the two costs people most often forget when sizing.