FreeToolStation

Stock Average Calculator

Average cost per share across any number of purchases.

Finance Calculators Free, no sign-up Runs in your browser

Optional, for profit and loss.

Added to your cost basis.

Shares then price. For example "100, 50" is 100 shares at 50 each.

—
Average cost per share
—
Total shares
—
Total invested
—
Value now
—
Profit or loss
PurchaseSharesPriceCostRunning average

About the Stock Average Calculator

Stock Average Calculator works out the average price you have paid across every purchase of the same holding. It is a weighted average, not a plain one: buying a hundred shares at fifty and a hundred and fifty at forty-two averages to 45.20, not 46, because the larger purchase counts for more.

The average is also your break-even price, which is what makes it worth tracking. Below it the position is losing money and above it the position is making money, regardless of what any single purchase cost. Dealing fees belong in the cost basis for the same reason: they are money spent on the holding, and leaving them out makes the break-even look lower than it is.

A caution about averaging down. Buying more of something that has fallen does lower the average and does lower the price at which you break even, which is the arithmetic. It also increases the amount you have riding on a position the market has marked down, which is the risk. The calculator tells you the first; only you can judge the second.

This is arithmetic, not financial advice. It tells you what the numbers do; it cannot tell you whether a decision is right for your circumstances. Fees, taxes and local rules vary, so check anything that matters against the actual offer and speak to someone qualified before committing.

Everything is worked out inside your browser. Nothing you enter is uploaded, logged or stored, which matters for the financial calculators in particular: the figures you put into them are nobody else's business.

How to use the Stock Average Calculator

  1. Enter current price, total dealing fees and your purchases, one per lineDecimals are fine, and thousands separators are accepted and ignored.
  2. Read the average cost per share, total shares and total investedThe figures update as you type. The Calculate button is there if you would rather press something, but nothing waits for it.
  3. Copy or check the resultCopy the summary with the copy button, or open the table to check it row by row.

Features

  • Shows average cost per share, total shares, total invested, value now and profit or loss together, so you are not running it twice
  • A results table you can read across
  • Updates as you type, with no button to press and no page reload
  • Copy the result in one click
  • Free, no sign-up, and it runs entirely in your browser

Who uses this tool

The stock average calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

  • Finding the break-even price across several purchases
  • Working out what averaging down would do to your cost
  • Keeping a cost basis for a tax return
  • Checking the profit on a position at today's price

Frequently asked questions

How do I enter my purchases?

One per line as shares then price, separated by a comma, a space or an "at" sign. "100, 50" and "100 x 50" both mean a hundred shares at fifty.

Should I include fees?

Yes, in the fees field. They are part of what the holding cost you, so they raise your break-even price.

Does averaging down reduce risk?

It reduces your average price and increases your exposure. Whether that is sensible depends entirely on why the price fell, which is not something arithmetic can tell you.

If the stock average calculator is not quite what you need, these other free tools solve closely related problems, and there are 38 more in finance calculators.

ROI Calculator

Net gain, ROI and the annualised figure from what you put in and got out.

Finance Calculators Use tool

CAGR Calculator

The smoothed yearly growth rate between a starting and an ending value.

Finance Calculators Use tool

Checked and rebuilt on 2026-10-14. The method this calculator uses is described in the section above, and corrections go through the contact page.