Something wrong with this tool?
About Average Share Price Calculator Online
This tool calculates your weighted average cost per share across multiple stock purchases. Enter each transaction's quantity and price, and it returns the blended cost basis — the figure brokers and tax software use when reporting gains or losses.
Calculating an average cost is essential when you've dollar-cost averaged into a position over time, bought lots at different prices, or are deciding whether to add to a holding to lower your break-even. The result depends on the share quantities, not just the prices, so a few large purchases can dominate many small ones.
Use it before placing additional buy orders to see exactly where your break-even sits, or when reconciling your records against a brokerage statement.
How to use this tool
How to compute the average price you paid for a position
Enter total cost
"Total cost" is the sum of every buy you've made for this position, including commissions and fees if you want "all-in" cost basis. Use the same currency you'll quote the price back in.
Total shares accumulated
"Shares" is the total number of shares you currently hold from those buys. Zero shares throws "Shares cannot be 0." — there's no "average price" without a position.
Press Run
Result is averagePrice = totalCost / shares, rounded to 6 decimals. This is dollar-cost-average (DCA) for cost basis — useful for tax-lot tracking and break-even analysis.
Excludes sells and dividends
The tool doesn't model partial sells (which would reduce both cost basis and share count) or reinvested dividends. For a real broker-style cost basis with multiple tax lots, use a portfolio tracker.