Position Sizer

About

Enter your account size, the percentage you are willing to lose on a trade, and where your entry and stop are. It tells you how many shares (or option contracts) to buy so that being stopped out costs no more than that percentage. Add a target to see reward against risk, and the prices that sit 1R, 2R and 3R from your entry.

How do I calculate position size?

Risk amount = account size x risk percentage. Risk per share = the distance between entry and stop. Shares = risk amount / risk per share, rounded down. For a 10,000 account risking 1% (100) with an entry of 50 and a stop of 48, the risk per share is 2, so the size is 50 shares, a 2,500 position.

Why is the size rounded down?

So a stop-out can never cost more than the amount you chose. If the maths says 33.3 shares, the tool shows 33, and the real risk is a little under your budget.

What risk percentage should I use?

That is a personal choice and the tool takes no view. Many people start around 1% per trade, but it only does the arithmetic for whatever you enter.

How does it size options?

For long calls or puts, the risk per contract is the premium (or the premium minus your stop premium) times the multiplier, usually 100. Contracts = risk amount / risk per contract, rounded down. Leave the stop premium blank to size for the whole premium going to zero.

What do 1R, 2R and 3R mean?

R is your risk per share. 1R is the price one risk-distance from entry in the direction of the trade, 2R is two, and so on. Reward : risk is the distance to your target divided by the distance to your stop.

Are my numbers saved?

Only your account size and risk percentage are remembered, in this browser, so you do not retype them. They are never sent anywhere, and Clear saved removes them. Prices for a trade are never stored.

Is this financial advice?

No. It is arithmetic on the numbers you enter. A stop is not guaranteed to fill at your price: gaps, thin markets and trading halts can lose more than the risk shown, and fees are not included.