Find your weighted average cost per share across several buys.
Calculated instantly in your browser.
How do you calculate the average price per share?
Average price = total amount invested ÷ total shares owned, where each buy contributes shares × price to the total cost. For example, buying 10 shares at 100 and 20 shares at 70 gives 30 shares for 2,400 — an average of 80 per share. This is your cost basis, the break-even price for the whole position.
Understanding your result
This is your cost basis, the break-even price for the whole position. “Averaging down” by buying more at a lower price pulls this number toward the cheaper buys.
Formula and method
Average price = total amount invested ÷ total shares owned. Each buy contributes shares × price to the total cost.
Assumptions and limitations
The result is an estimate for general guidance only and not investment advice. It reflects only the buys you enter and ignores trading commissions, taxes, dividends and currency effects unless you build them in. Your true cost basis for reporting may follow specific rules where you live, so confirm important figures with a qualified professional.
Worked example
Buying 10 shares at 100 and 20 shares at 70 gives 30 shares for 2,400 — an average of 80 per share.
How to use this tool
- Enter the shares and price for each buy.
- Leave the optional rows blank if you only have one or two buys.
- Press Calculate.
About the Stock Average Price Calculator
The Stock Average Price Calculator works out your weighted average cost per share when you have bought the same stock at different prices.
Who should use this tool
Investors who have bought the same stock at different prices and want their weighted average cost per share. Useful for tracking your cost basis, working out the position's break-even price, and seeing how buying more shares at a new price moves your average up or down.
Benefits
- Combines several buys into one weighted average cost
- Reveals the break-even price for your whole position
- Shows how averaging down shifts your cost basis
- Keeps your holdings private in the browser
Practical use cases
- Finding your break-even price across multiple purchases
- Checking your average cost after buying more shares
- Seeing the effect of averaging down on cost
- Keeping a tidy record of a position's basis
Frequently asked questions
What is averaging down?
It means buying more shares after the price falls, which lowers your average cost per share but also increases the money at risk.
How is the weighted average different from a simple average of prices?
A simple average treats each price equally, but the weighted average accounts for how many shares you bought at each price. It divides your total money invested by the total shares owned, so a larger purchase pulls the average closer to its price, as in the 30-share, 2,400 example giving 80.
Does this tool include trading fees or commissions?
By default it works from the share prices and quantities you enter, so any commissions are not added unless you fold them into the amounts. If fees matter to your cost basis, include them in the total invested for each buy so the average reflects what you truly paid.