Average Cost Basis Calculator

Combine several purchases of the same stock or fund into one average cost per share.

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Leave unused purchases blank.
Average cost per share
Total shares
Total cost
Current value
Unrealized gain or loss
Simple average of prices
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How to Calculate Average Cost Basis

Average cost = total amount paid ÷ total shares

Weight each price by the number of shares bought. Dollar-cost averaging (investing the same dollar amount on a schedule) buys more shares when prices are low, so its average cost comes out below the simple average of the prices.

Worked Example

Tips

For taxes, your broker may use first-in-first-out (FIFO) or specific lots rather than the average (mutual funds can use average cost). Include commissions in the price if you paid any. Merged: Dollar-Cost Averaging (C084) is covered here.