Position size calculator
Decide how many shares to buy based on what you're actually willing to lose — not on a round number that felt right.
How position sizing works
The idea is to flip the usual question. Instead of "how many shares can I afford," you ask "how much am I willing to lose if I'm wrong" — and let that decide the size. Most disciplined traders risk a small, fixed slice of their account per trade, often 1–2%.
The math is straightforward. Your risk amount is your account size times your risk percentage. Your risk per share is the distance from your entry to your stop-loss. Divide one by the other and you get the number of shares that keeps your loss capped at what you decided in advance:
shares = (account × risk%) ÷ (entry − stop)
The point of doing it this way is that a wide stop forces a smaller position and a tight stop allows a larger one — so a single loss costs you the same either way. Your downside stops being a surprise.
Educational tool, not financial advice. Everything runs locally in your browser; nothing is sent or stored.