Stock Average Calculator
Calculate your weighted average price per share across two purchases using their respective share counts and prices.
FREE ONLINE CALCULATOR
Stock Average Calculator
Change the settings below to calculate your result. You can check the assumptions further down this page.
Average cost = (shares 1 × price 1 + shares 2 × price 2) / (shares 1 + shares 2).
How to use this stock average calculator
Enter the shares bought and price per share in each purchase. The result reports the combined share quantity and average unit cost before fees.
Formula and calculation method
Average cost = (shares 1 × price 1 + shares 2 × price 2) / (shares 1 + shares 2).
Worked example
Buying ten shares at $20 and ten at $30 results in an average purchase cost of $25 per share.
Understanding the result
Weighted average purchase price is determined by shares and costs together. A larger purchase affects the average more than a smaller one. The result is a cost basis estimate and says nothing about whether future prices will rise.
When to use this calculator
For more than two transactions, group earlier purchases into their combined quantity and average cost, then use those as the first purchase. Adjust separately for fees, splits and other events if your recordkeeping requires them.
What the results do not include
Trading commissions, taxes, corporate actions and currency conversions are not included.
Frequently asked questions
Does buying at a lower price guarantee a profit?
No. Average cost describes purchase cost, not future market value.
Can I enter fractional shares?
Yes. Enter decimal share quantities.
For education and estimates only. Check any contractual, tax, banking or employment terms that apply to your situation. The calculations are not financial advice or guaranteed returns.