Trade Risk Calculator: Check Your Position Size Before You Buy
Use your proposed entry, stop, target, account balance, and share quantity to calculate the structure of a hypothetical stock trade before placing an order.
How the calculator works
|Entry price − stop price|
Risk per share × quantity
Planned dollar risk ÷ account value × 100
|Target − entry| ÷ |Entry − stop|
The absolute-value notation lets the arithmetic display for either direction, but short selling has risks that this simple calculator does not capture, including potentially unlimited loss as price rises, borrow availability, and buy-in risk. Use this page as a stock-trade arithmetic explainer—not as a complete short-sale or options-risk model.
Worked example
With a $25,000 account, a $50 entry, a $48 stop, a $55 target, and 100 shares:
- Risk per share is $2.
- Planned dollar risk is $200.
- Planned account risk is 0.8%.
- Position value at entry is $5,000.
- Potential reward per share is $5, producing a 2.5:1 reward-to-risk ratio.
That still does not answer whether the stock will reach $55 before $48. It also does not determine whether 0.8% is appropriate for a particular trader. Those are separate questions involving evidence, probability, portfolio context, time horizon, liquidity, and personal circumstances.
What this calculation leaves out
| Not modeled | Why it matters |
|---|---|
| Gaps and slippage | A stop order can execute at a price different from its trigger, particularly in fast or illiquid markets. |
| Fees and taxes | They change net outcomes and vary by account and jurisdiction. |
| Probability | A reward-to-risk ratio describes payoff distances, not the likelihood of either outcome. |
| Portfolio concentration | Several positions may share the same sector, factor, or market risk. |
| Options mechanics | Contracts add multiplier, premium, Greeks, volatility, liquidity, expiration, exercise, and assignment considerations. |
| Personal suitability | A mathematical result is not individualized advice or a personal risk limit. |
Go beyond calculator math
RichesReach Trade Check accepts a stock or option, side, entry, stop, target, account balance, and quantity. It combines the risk math with a plain-English verdict and can suggest a smaller quantity when the proposed size does not fit the applicable risk guardrails.
Run a Trade Check in RichesReachSources and further reading
Editorial note: This calculator performs simplified arithmetic from user-supplied figures entirely in the browser. It does not access live prices, place orders, predict outcomes, or provide individualized investment advice. Product descriptions were checked against the RichesReach Trade Check implementation on August 21, 2026.