Dashboard

Position Size Calculator

How much to buy so the stop costs exactly what it should

Long
I enter

Result

Position size
0.0500units of the underlying
Stop sits 4.00 % away from entry
Loss at stop
$200.00
2.00 % of the account
Position value
$5,000
Margin required
$1,000
Without leverage the position would need 0.5× your equity

How position size is derived

This page works both ways. Risk in % is classic risk management: risk in money (equity × percent) divided by the distance from entry to stop gives the number of units, so hitting the stop costs exactly the chosen percentage of the account. Position value asks the reverse question: you say how much you are putting into the trade and it tells you what the stop will cost.

Leverage does not enter the size calculation. It only changes how much margin the position locks up — not how much the stop costs. That is the most common confusion: 10× leverage does not make the position bigger, it frees up capital and moves the liquidation price closer to entry.

One percent of the account per trade is the common setting, two for the more aggressive. The calculation ignores fees, slippage and the fact that a stop can gap through on a volatile market — the real loss tends to be somewhat larger.