Stock Position Size Calculator

Choose a dollar risk budget, then divide it by the risk per share. Risk per share is entry price minus stop price for a long stock trade. A $1,000 budget and $2 entry-to-stop distance produce 500 theoretical shares.

It is the loss you plan for if this one position exits at the exact stop price. It is not the position's purchase value and it is not a guaranteed maximum loss, because real execution can occur above or below the entered stop.

Multiply account value by the percentage expressed as a decimal. For example, 1% of $100,000 is $1,000. The percentage and dollar fields on this page stay synchronized so either can be the value you type.

For the long-stock model here, it is entry price minus stop price. Buying at $50 with a stop at $48 gives $2 of planned risk per share before any gap, slippage, fee, or tax.

The stop distance sets planned risk per share. A wider distance means more dollars at risk on each share, so fewer shares fit the same total budget. A tighter distance produces more shares, which can also increase position value and concentration.

Yes. Edit the dollar risk budget directly and the percentage updates from account value. The calculator remembers which risk field you edited last and preserves that value when another input changes.

Position value is shares multiplied by entry price. Planned risk is shares multiplied by the entry-to-stop distance. A $25,000 stock purchase can therefore show $1,000 of planned stop-defined risk, while the full position remains exposed to larger moves.

Rounding up could put planned risk above the selected budget. If the formula produces 333.33 shares, whole-share mode returns 333. The theoretical count remains visible for reconciliation.

It is the chosen dollar budget minus planned risk after the share count is rounded or cash-capped. Whole-share sizing commonly leaves a small amount unused because part of a share cannot be purchased in that mode.

It is position value divided by account value. FINRA describes concentration risk as amplified loss potential from placing a large portion of holdings in one investment or market segment. The calculator reports exposure but does not prescribe a limit.

Risk sizing can produce a position larger than the cash you intend to commit, especially when the stop is close to entry. When a cash cap is entered, the calculator uses the lower of risk-sized shares and cash-capped shares.

In whole-share mode, the risk budget or cash cap may be too small for one complete share at the entered prices. Open the optional panel to view a fractional estimate, but check that the broker and security support fractional trading.

No. The SEC explains that a stop order normally becomes a market order when triggered, and the execution price can differ significantly in a fast market. The calculator therefore calls the output planned risk at the stop price.

Yes. A gap, rapid price move, limited liquidity, delayed trigger, fees, or an order that does not execute can make the realized loss larger. The result is arithmetic under the entered prices, not a guarantee.

A triggered stop order may execute near the next available market price rather than at the stop. If that price is lower, actual risk per share is larger than the entry-to-stop distance used by the calculator.

A stop order generally becomes a market order when triggered, so execution is likely but the price is not guaranteed. A stop-limit order controls the acceptable price, but the SEC warns that it may not execute if the market moves through the limit.

A smaller entry-to-stop distance lowers calculated risk per share. Dividing the same budget by that smaller number permits more shares. That mathematical result does not mean the tighter stop is sensible or less likely to trigger.

No. It only calculates from the price you enter. Stop selection is a separate decision involving the security, strategy, volatility, liquidity, time horizon, and tolerance for loss.

Yes. Open the optional panel and select the fractional estimate. The result is rounded down to six decimals, but a broker may support a different increment or permit only dollar-based orders.

No. SEC investor bulletins note that availability, eligible securities, order types, execution practices, minimums, and platform restrictions can vary. Check the current agreement and order ticket at the broker that will execute the trade.

No. Those values do not change the basic share-count formula and differ by broker, account, security, and taxpayer. Their omission means actual cash required and realized loss can differ from the displayed plan.

No. This page models one long stock position in shares. Short sales, option contracts, forex lots, crypto leverage, and futures tick values have different sizing and loss mechanics and need separate tools.

No. The optional cash cap assumes the position cannot exceed the cash amount you enter. If borrowing is involved, use the linked stock margin calculator to model cash contribution, loan, interest, and maintenance requirements separately.

No. You enter every number and the calculation runs locally in the browser. There is no ticker lookup, account connection, portfolio storage, cookie identifier, or server request containing the calculator inputs.

No. It is transparent arithmetic using your assumptions. It does not assess whether the stock, entry, stop, account risk, position concentration, or strategy is appropriate for you.

Available cash, settled funds, buying power, minimum order size, fractional increments, current quote, fees, security restrictions, and margin rules can all change what an order ticket accepts. The broker's live order controls.