← Blogby Marcell Almeida

How to calculate average stock purchase price

Add each buy lot — shares and price — to get your weighted average cost per share.

After several buys at different prices, your true cost basis is a weighted average — not the last trade price. The Stock Average Price Calculator totals shares and computes average cost instantly.

Try it — enter shares and price per lot

Open full tool →

How it works

  1. Add lots — shares purchased and price per share for each trade.
  2. Review average — weighted average cost and total shares.
  3. Compare to market — use average cost for gain/loss decisions.

Weighted average

Average cost = total amount paid ÷ total shares. A larger lot at a higher price pulls the average up more than a small lot.

DCA modeling

For recurring investments over time, try the Dollar Cost Averaging Calculator.

The How to calculate average stock purchase price is free, runs locally, and never sends your data to a server. More finance calculators at maratool.com.