Position Size Calculator: Shares to Buy for Your Risk

Trading position size: the risk-per-trade formula explained

Number of units = (account size × risk %) ÷ |entry price − stop loss|. With a $10,000 account, 1% risk, an entry at 150 and a stop at 145, you buy 20 units, a $3,000 position with a maximum loss of $100 if the stop is hit.

Calculation steps.

1. Amount at risk = account size × risk / 100.
2. Stop distance = |entry − stop|. Direction is inferred: stop below entry means a buy (long), stop above means a short sale (short).
3. Units = amount at risk ÷ stop distance.
4. Position value = rounded units (as displayed) × entry price; effective leverage = position ÷ account size.
5. Risk/reward ratio = (take profit − entry) ÷ stop distance for a long, (entry − take profit) ÷ stop distance for a short, shown in green from 1:2.

Example

Defaults: $10,000 account, 1% risk, entry at 150, stop at 145, target at 165. Amount at risk $100; distance 5; 20 units; $3,000 position; leverage x0.3; ratio 1:3.0. With a tighter stop at 149, the same $100 risk allows 100 units, a $15,000 position and x1.5 leverage: the closer the stop, the larger the position.

Assumptions and limits

• The stop is assumed to fill exactly at its price: slippage, spread, fees or an opening gap can make the real loss larger.
• One unit equals one price point: there is no contract multiplier or pip value. For a future or a currency pair, first convert the stop distance into an amount per unit.
• Below 10 units the result keeps 4 decimals (useful for crypto); above that it is rounded down to a whole unit.
• A take profit on the wrong side of the entry (below it for a long, above it for a short) gives a ratio of 1:0.0.
• The position is not capped by the account: leverage above 1 assumes a margin account.
• The risk slider runs from 0.1% to 10%; the currency symbol is the dollar in English and the euro in the other languages.

Calculation tool only, not investment advice.

Frequently Asked Questions

How do you calculate position size from a stop loss?

Divide the amount you are willing to lose by the distance between entry and stop. With a $10,000 account and 1% risk you risk $100; an entry at 150 and a stop at 145 give a distance of 5, so 100 ÷ 5 = 20 units, or $3,000 invested.

What percentage of my account should I risk per trade?

The tool shows benchmarks: 0.5% (conservative), 1 to 2% (standard), 5% and above (aggressive). The difference adds up fast: ten losses in a row cost about 9.6% of the account at 1% per trade, 18.3% at 2% and 40.1% at 5%. A small percentage lets you survive a losing streak without draining the account.

Where should I place my stop loss?

At a technical level where your trade idea is invalidated, for example below support for a long or above resistance for a short. Position size then adapts: at a constant $100 risk, a stop at 149 instead of 145 takes you from 20 to 100 units. A stop that is too tight gets hit more often by ordinary market noise.

What does a 1:3 risk/reward ratio mean?

The target gain is three times the accepted loss: 15 points of target for 5 points of stop in the default example. At 1:3 you only need to win one trade in four (25%) to break even, before fees. The tool shows the ratio in green from 1:2.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.