Stock Average Calculator

Average down or up across multiple stock purchases, enter each buy’s shares and price to get your total shares, total cost, and average cost per share.

Average price per share

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Total shares-
Total cost-

Show the math

The average is your total cost spread over your total shares:

avg price = Σ(shares × price) / Σ shares

Each purchase is weighted by how many shares it bought, giving your weighted average cost basis. Buying more shares at a lower price pulls the average down (averaging down); buying higher pulls it up. Add a row for each purchase, blank rows are ignored.

What this does

A stock average calculator finds your weighted average cost per share across multiple purchases. Enter each buy’s shares and price to get your total shares, total cost, and average cost basis.

How it works

For each purchase, multiply shares by price, sum those costs and the share counts, then divide. The result is your weighted average cost basis across every buy.

Average = total cost ÷ total shares

How to use it

  1. Add a row for each purchase with its shares and price.
  2. Add as many rows as you need; empty rows are ignored.
  3. Read your total shares and total cost.
  4. See your average cost per share.

Understanding your result

Buying more shares below your earlier price (averaging down) lowers your average cost, so the price needs to recover less for you to break even. It does not, on its own, make a holding a good investment.

Example

Buying 10 shares at $100 and 10 at $80 gives 20 shares for $1,800, an average cost of $90 per share.

Sources & methodology

Last updated .

Frequently asked questions

How is the average price calculated?

It is your total cost divided by your total shares: add up shares × price across every purchase, then divide by the total number of shares. This is your weighted average cost basis.

What is averaging down?

Buying more shares at a lower price than your earlier purchases pulls your average cost per share down, so the price needs to recover less for you to break even.

Can I add more than two purchases?

Yes, add a row for each buy. Empty rows are ignored, so you can compare a few scenarios quickly.

Is anything saved?

No. All math happens in your browser; nothing you type leaves your device.