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Free calculator

Average share cost calculator

Combine two purchases of the same security using quantity-weighted prices.

Weighted price per share

Enter your assumptions to calculate.

Same security and currency. Fees and taxes are excluded.

What this calculation assumes

For two purchases of the same security in the same currency. Excludes fees, sales, taxes, splits and other corporate actions. This arithmetic average is not necessarily your tax cost basis.

The formula

Average price = (first quantity × first price + second quantity × second price) ÷ total quantity. Total quantity must be greater than zero.

Inputs remain in your browser. Results are educational estimates, not recommendations or guaranteed outcomes.

Read: A stock split changes the slice, not the whole pie