Your blended cost per share across purchases, and the price at which the whole position breaks even.
Commissions and other purchase costs for all buys.
Example Result
Your result will appear here
The calculated result will appear here after you press Calculate.
Estimates for planning only; not financial, tax or investment advice. See our Disclaimer.
Buy 100 shares at $50 and another 50 at $40, and your average price is not $45 — it is $46.67, because more of your money went in at $50. The average cost per share is total money spent divided by total shares, a weighted average. It tells you the price at which the whole position breaks even and is the figure most brokerage apps show next to a holding. Enter two purchases, or switch to "Many purchases" and list every buy as shares @ price; add total fees if you paid any. The calculator returns the average price, the total shares and the total cost. The guide below covers averaging down, commissions, what happens to the average when you sell, and one important limit: for US taxes on individual stocks, the average is not the cost basis you report.
Enter the shares and price of each purchase — two in the first mode, any number as "shares @ price" in the second.
Add total commissions or fees if you paid any.
Press Calculate to see your average cost per share.
By O.E. — Partner, chairman of the board and CEO of a metal products manufacturer for 21 years; the company exports to 45 countries.
Drafted with AI assistance; calculations checked against primary sources and tested with the site's own code. About FlowUtil
Last reviewed
Average price = (shares₁ × price₁ + shares₂ × price₂ + … + fees) ÷ (shares₁ + shares₂ + …). Buying 100 shares at $50 and 50 at $40 costs $7,000 for 150 shares: $46.67 a share. A simple average of the two prices ($45) would be right only if you had bought the same number of shares each time. Commissions and other purchase fees are part of what you paid — two $5 commissions make the cost $7,010 and the average $46.73.
| Symbol | Meaning |
|---|---|
| Shares @ price | Each purchase, e.g. 100 @ 50 |
| Fees | Total commissions and purchase costs |
| Average | Total cost ÷ total shares — the break-even price for the position |
1100 shares at $50, then 50 at $40.
7,000 ÷ 150
Average $46.67
The stock now has to climb back to $46.67, not $50, for the position to break even — 16.7% from $40 instead of 25%.
2A third purchase: 100 @ 50, 50 @ 40, 50 @ 35.
8,750 ÷ 200
Average $43.75
Each purchase lowers the average only by adding more money to the same bet: the amount at risk is now $8,750.
3100 at $48.20, then 150 at $41.60.
11,060 ÷ 250
Average $44.24
The larger second lot pulls the average towards $41.60.
410.5 shares at $200 and 4.25 at $180, $10 of fees.
2,875 ÷ 14.75
Average $194.92 ($194.24 before fees)
Fractional shares work the same way.
Selling part of a position does not change the average price of the shares you keep in this calculation — you remove shares at the average. Tax rules are different. For individual stocks in the US, the IRS does not let you use the average price per share to figure the gain or loss on a sale: the basis is that of the specific lot you identify as sold, and if you cannot identify it, the shares you bought first (first-in, first-out). Selling 50 shares from the first example under FIFO uses the $50 lot; identifying the $40 lot instead gives a larger gain on paper today. Average basis is allowed for mutual fund shares and certain dividend-reinvestment-plan shares (IRS Publication 550). Tax rules in other countries differ — the UK, for example, pools shares of the same company.