Understanding stock average calculator
A larger purchase lot has more influence on the average cost than a small lot. Weight each price by the shares acquired rather than taking a simple mean of prices. The result is a purchase-cost summary; selling shares or determining taxable gains may require a separate lot-accounting method.
Formula and calculation method
Weighted average acquisition price = [sum(price × quantity) + entered acquisition fees] / total quantity.
Acquisition-cost arithmetic across purchase lots. This is not FIFO tax-basis accounting and does not process sales, corporate actions, dividends or foreign-exchange changes.
How to use stock average calculator
- Set Purchase prices per share. The example below uses 100, 120, 90.
- Set Shares bought in corresponding lots. The example below uses 10, 20, 10.
- Set Total acquisition fees. The example below uses 0.
- Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.
Worked example
Example inputs
- Purchase prices per share
- 100, 120, 90
- Shares bought in corresponding lots
- 10, 20, 10
- Total acquisition fees
- 0
- Total shares
- 40
- Total acquisition cost
- 4300
- Average cost per share
- 107.5
Factors affecting your result
Acquisition-cost arithmetic across purchase lots. This is not FIFO tax-basis accounting and does not process sales, corporate actions, dividends or foreign-exchange changes.
Changing purchase prices per share changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.
Frequently asked questions
How does the stock average calculator work?
Weighted average acquisition price = [sum(price × quantity) + entered acquisition fees] / total quantity.
What inputs does Stock Average Calculator need?
Enter purchase prices per share, shares bought in corresponding lots, total acquisition fees. Choose values that correspond to the same situation and measurement convention.
How should I interpret the stock average calculator result?
Acquisition-cost arithmetic across purchase lots. This is not FIFO tax-basis accounting and does not process sales, corporate actions, dividends or foreign-exchange changes.
Are my stock average calculator inputs uploaded?
No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.
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