Calculate

Cost Basis Calculator

See how buying more shares changes your average cost, or how selling shares affects your realized P&L and remaining cost basis. Supports averaging down, averaging up, and trimming.

Current Position

Shares Owned

How many shares you currently hold

Avg Cost Per Share

New Purchase

Shares to Add

Purchase Price

Result

New Avg Cost—

Change from Current Avg—

Total Shares After—

Total Cost Basis—