Calculate the exact number of shares or units to trade based on your capital, risk percentage, and stop-loss. Never accidentally over-size a position again.
Enter capital, risk %, entry price, and stop-loss to get the correct position size.
HOW IT WORKS
Set your total trading capital and the maximum % you are willing to risk on a single trade. 1-2% is standard for most traders.
The difference between entry and stop-loss determines the risk per share. The calculator uses this to find how many shares to buy.
Buy this many shares — no more, no less — and your maximum loss on the trade is exactly your risk amount, regardless of how far price moves against you.
FAQ
Even the best entry can blow an account if the position size is too large. Position sizing determines survival. A trader with mediocre entries and good position sizing will outlast a trader with great entries and reckless sizing every single time.
The 2% rule means risking no more than 2% of your total capital on any single trade. At 2% risk, you can survive 50 consecutive losses before losing your account — statistically nearly impossible even for poor strategies. Most professional traders risk 0.5-1%.
Some traders scale position size based on setup quality — smaller for uncertain setups, larger for high-conviction setups. However, beginners should use a fixed size (e.g., always 1%) until they have enough statistical data to know which setups are actually higher probability.
For options, use the premium as entry price and your acceptable premium loss as the stop-loss distance. For futures, use the price levels directly but remember lot size — the quantity shown is in units, so divide by lot size to get the number of lots.
Enforce your position sizing rules automatically
TradeLyser tracks your actual position sizes vs your rules, flags when you've over-sized, and shows your real risk per trade over time.