Free tool / Linear perpetuals
Position-size calculator
Define the risk. Plan the size. Estimated fees and slippage are included.
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How the calculation works
This calculator models a linear, quote-margined position. It uses the prices and cost assumptions you enter; there is no live market or exchange connection.
The fee-inclusive model
Risk budget = account equity × risk percentage. Position notional = risk budget ÷ (stop distance + slippage allowance + two fees). All percentages are converted to fractions.
Margin = notional ÷ selected leverage. Quantity = notional ÷ entry price. Both entry and exit fees are approximated using entry notional; real exit fees can differ.
A worked example
With $1,000 equity, 1% risk, entry 100, stop 95, 0.1% slippage and 0.05% fee per side: the risk budget is $10, notional is approximately $192.3077, and modeled loss is $10. At 10× leverage, estimated margin is $19.2308. These are illustrative inputs, not current exchange fees or a trade recommendation.
What the model leaves out
Funding, changing maintenance tiers, liquidation fees, mark-price effects, other open positions and execution gaps. A stop can fill worse than planned, and actual loss can exceed the modeled budget. Check contract specifications and platform calculations before acting.