Position Size Calculator

Size the trade from your risk, not from your feelings — the one habit that keeps losing streaks survivable.

How it is calculated

position = (account × risk%) / stop distance%   |   margin = position / leverage

Professional sizing works backwards: decide the dollars you are willing to lose first, measure the distance to your stop, and let those two numbers dictate the position. Leverage then only determines how much margin gets locked — it does not change your risk if the stop is respected.

Worked example

A $5,000 account risking 1% ($50) on a long from $60,000 with a stop at $58,800 (2% away): position = $50 / 0.02 = $2,500. At 10x that locks just $250 of margin — and whatever happens, the loss if the stop fills is $50, exactly 1%.

FAQ

What risk percentage should I use per trade?

Most systematic traders risk between 0.5% and 2% of the account per trade. At 1% you can take 20 consecutive losses and still keep ~82% of the account; at 5% the same streak leaves you with ~36%. The right number is the one that lets you follow the plan through a normal losing streak.

Does higher leverage mean higher risk here?

Not if the stop is honored. With risk-based sizing, leverage only decides how much margin is locked as collateral — the dollar loss at the stop stays the same. Leverage becomes dangerous when the stop is skipped or the position is sized from margin instead of from risk.

What if my stop is very tight?

A tighter stop allows a larger position for the same dollar risk — but it also gets hit more often by normal noise. Check the average candle range on your timeframe before placing a stop closer than the market naturally wiggles.

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Free, no signup, runs entirely in your browser. Educational tool — not financial advice. Practice the setup risk-free on the MarginPad paper-trading terminal before putting real money behind it.