Position Size Calculator

Work out how many shares to buy so that a trade risks only a fixed percentage of your account if the stop-loss is hit.

%
Position size
33 shares
Amount at risk
100.00
Risk per share
3.00
Position value
1,650.00
Share of account used
16.50%

Formula

Shares = (Account size × Risk %) ÷ |Entry price − Stop-loss price|

About this calculator

Position sizing keeps the loss on any single trade to a set fraction of your capital. Many traders risk 1% to 2% per trade. The result is rounded down to whole shares. Results are estimates for education and planning. They are not financial advice, and real returns are never guaranteed.

Amounts are shown without a currency symbol, so the calculator works for any currency: enter all values in the same one.

Frequently asked questions

Will my loss always be limited to this amount?

Not always. A price can gap past your stop-loss, and the order then fills at a worse price, so the real loss can be larger.

Does it work for forex or crypto?

The principle is the same, but lot sizes and pip values differ. Use it for instruments priced per unit, such as shares and ETFs.

Related tools

Rule of 72 CalculatorEstimate how many years it takes to double your money at a given annual return, with the exact figure for comparison. Compound Interest CalculatorCalculate compound interest with yearly, quarterly, monthly or daily compounding and optional monthly contributions. Simple Interest CalculatorCalculate simple interest and the total amount from principal, annual rate and time. Loan EMI CalculatorCalculate the monthly instalment (EMI), total interest and total repayment for a personal, car or home loan. Mortgage CalculatorEstimate your monthly mortgage payment including principal, interest, property tax and home insurance. Savings Goal CalculatorFind out how much to save each month to reach a target amount by a set date, including growth on what you already have.