Important limitation
Average cost is not permitted for every asset or election. Confirm broker records and applicable tax-lot rules before reporting a sale.
Cost Basis Calculator
Combine purchases using average cost and allocate basis between sold and remaining shares.
Realized gain / loss
$1,380
38.3% on allocated basis.
Average basis per share$60
Basis of shares sold$3,600
Remaining shares90.000
Remaining basis$5,400
Net sale proceeds$4,980
Uses average cost. Tax rules may require specific identification, FIFO, wash-sale adjustments, reinvested distributions, splits, or broker records.