Calculate your average cost basis after multiple stock / ETF purchases
Total Shares Owned:0
Total Capital Invested:$0.00
Average Cost Per Share:$0.00
Current Portfolio Value:$0.00
Unrealized Profit / Loss:$0.00
Unrealized Return:0.00%
Disclaimer: This tool provides estimated cost basis for reference only. All calculations run locally within your browser, no data is transmitted externally. Do not use as official tax documentation without cross-verification with your brokerage statements.
How This Calculator Works
This average cost calculator computes your weighted average cost basis when you buy the same stock or ETF at different prices. It supports fractional shares widely available on US trading platforms. Simply add every separate buy transaction. After entering the latest market price, you can view your current portfolio value and floating profit or loss. This metric is essential for tracking investment performance and preparing capital gains tax reports.