Markets & Investing
Average stock purchase cost
Use this average stock purchase cost calculator to combine purchase lots and fees into a weighted average per share.
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
average purchase cost = sum(shares × price + fees) / sum(shares)
Purchase-only arithmetic. Exclude sold lots and adjust share counts/prices for splits before entering. This is not an election or calculation of tax cost basis, wash-sale adjustments or realized gains. 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
- Purchase lots only: Use matching records or an explicitly identified assumption for purchase lots only. Unknown is not the same as zero.
- Shares in this purchase (shares): Use matching records or an explicitly identified assumption for shares in this purchase. Unknown is not the same as zero.
- Price per share (selected currency): Use matching records or an explicitly identified assumption for price per share. Unknown is not the same as zero.
- Fees for this purchase (selected currency): Use matching records or an explicitly identified assumption for fees for this purchase. 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: Weighted acquisition cost per share is $21.40 for the illustrative inputs below.
Example inputs
- Purchase lots only
- Shares in this purchase: 100.00 shares
- Price per share: $20.00
- Fees for this purchase: $5.00
- Shares in this purchase: 50.00 shares
- Price per share: $24.00
- Fees for this purchase: $5.00
- Weighted acquisition cost per share
- $21.40
- Total shares purchased
- 150.000000 shares
- Total purchase cost including fees
- $3,210.00
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Use this average stock purchase cost calculator to combine purchase lots and fees into a weighted average per share.
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.