Numveo
Investment

Cost Basis Calculator (Average Down)

Buying more of a falling stock lowers your average cost. Find your new average cost per share across two purchases.

Your details

Average cost per share
$43.33
Total shares
150
Total invested
$6,500.00
Average cost per share$43.33

Formula

Average cost = total invested ÷ total shares.

Sources & methodology

Last updated: 2026-07-20

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