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
- •U.S. SEC — stocks — SEC
Last updated: 2026-07-20
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