SizeGuard

Home › Guides › Position sizing for prop firm accounts

Position sizing for prop firm accounts

In a prop firm account the real limit is the drawdown, not the balance.

The rules that matter for size

• Daily loss limit: the most you may lose in one day. Hit it and the day (or the account) is over.
• Maximum drawdown: how far the account may fall from its start, or from its highest point if the drawdown trails.
• Contract limits: a cap on how many contracts you may hold.

Rules differ by firm and plan, so read your firm’s current rules.

A simple way to size

Decide how many losing trades in a row you want to survive before the drawdown is gone. If your account allows a $2,500 drawdown and you want room for 10 losses, risk $250 per trade. Then make sure a few of those can never break the daily loss limit: with a $1,000 daily limit, 3 full losses ($750) still leave room for slippage and fees.

Worked example

$250 risk on ES with a 16-tick stop: one ES risks $200.00, so the calculator suggests 13 MES ($260.00). With a 40-tick stop, one ES risks $500.00, over your $250, so you get 5 MES ($250.00).

Keep the costs in view

Evaluations, resets and activation fees add up. Use the free prop firm break-even calculator to see if payouts have covered them.