Position Size Calculator
Size every trade so a stopped-out loss costs you a fixed percentage of your account. This is the core habit of disciplined traders.
How position sizing works
Shares = (Account × Risk %) ÷ (Entry − Stop)
With a $25,000 account and 1% risk, you can lose $250 on the trade. If your stop is $2.50 below entry, you buy 100 shares. A tighter stop means more shares and a wider stop means fewer, but the dollar risk stays the same.
Most professional traders risk 0.5–2% per trade. At 1%, even ten losers in a row leave about 90% of your account intact.
Works for short trades too: put the stop above the entry.
Common questions
What percentage should I risk per trade?
1% is the most common guideline. Beginners often use 0.5% while building a track record. Risking over 2% makes losing streaks very costly.
Does this include slippage and commissions?
No. Gaps can push fills past your stop. To leave room for that, enter a slightly lower risk percentage.