Markets & Investing
Stock position sizing
Use this stock position sizing calculator to cap whole-share size by an entered risk budget and available cash for a long position.
Your inputs
Complete only the fields for your selected method. Use one consistent job or reporting period. Zero means intentionally zero, not unknown. Missing costs and market rates are not added automatically. Currency selection labels amounts; it does not convert exchange rates.
How this calculation works
shares = floor(min((risk budget - fixed fees) / (entry-stop), (cash-fixed fees)/entry))
A stop is an assumption, not a guaranteed execution price. Gaps, slippage and fees that depend on trade size can exceed this risk budget. Long unleveraged shares only, no margin, short sales, options, lot-size constraints or recommended risk percentage. Educational arithmetic from entered figures, not an investment recommendation, valuation opinion, forecast or guarantee. Taxes, inflation and foreign-exchange changes are excluded unless explicitly entered. Use one currency throughout; currency selection only changes labels.
What information do I need?
Use records for the same job, equipment or accounting period. Only the fields for your selected entry method are required. An unknown amount is not zero.
Input definitions and where to find them
- Account value used for risk budget (selected currency): Use matching records or an explicitly identified assumption for account value used for risk budget. Unknown is not the same as zero.
- Maximum modeled account risk (%): Use matching records or an explicitly identified assumption for maximum modeled account risk. Unknown is not the same as zero.
- Entry price per share (selected currency): Use matching records or an explicitly identified assumption for entry price per share. Unknown is not the same as zero.
- Assumed exit stop price per share (selected currency): Use matching records or an explicitly identified assumption for assumed exit stop price per share. Unknown is not the same as zero.
- Cash available for this position (selected currency): Use matching records or an explicitly identified assumption for cash available for this position. Unknown is not the same as zero.
- Total fixed entry and exit fees reserved (selected currency): Use matching records or an explicitly identified assumption for total fixed entry and exit fees reserved. Unknown is not the same as zero.
Use the Where to find this value controls beside the inputs for available work-it-out helpers. Estimates remain your assumptions; a helper does not verify the source figures.
Worked example
Example amounts use US dollars (USD).
Example answer: Whole shares within both modeled limits is 45 shares for the illustrative inputs below.
Example inputs
- Account value used for risk budget: $10,000.00
- Maximum modeled account risk: 1.00 %
- Entry price per share: $50.00
- Assumed exit stop price per share: $48.00
- Cash available for this position: $5,000.00
- Total fixed entry and exit fees reserved: $10.00
- Whole shares within both modeled limits
- 45 shares
- Modeled loss at supplied stop including fees
- $100.00
- Cash reserved including fees
- $2,260.00
- Entered risk budget
- $100.00
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Use this stock position sizing calculator to cap whole-share size by an entered risk budget and available cash for a long position.
Keep inputs on the same scope and time basis. Calculations retain precision internally; displayed values generally round to two decimal places, with extra precision for very small values and whole-unit rounding where required. Economic comparisons describe your supplied assumptions and do not guarantee future results.
This tool provides business arithmetic. It does not approve engineering designs, establish legal or tax treatment, select equipment or certify safe operating conditions.