What is average stock cost?
Average (or weighted average) cost per share shows the true average price you paid across multiple purchases of the same stock at different prices, which is used to determine cost basis for gains and losses.
The formula
Average Price = Total Amount Invested / Total Shares Purchased. Buying more shares when the price is lower (dollar-cost averaging down) reduces your average cost, while buying more at higher prices raises it.
This calculator is for general investment education, not investment or tax advice.
Last reviewed August 2026