Stock Average Price Calculator
Enter your purchases to get the average price per share, with and without fees. Find how many shares bring your average to a target, and your break-even sell price.
Your purchases
Averaging down or up to a target price
Commissions are entered as a percentage of each trade. Taxes on gains are not included.
How to use the Stock Average Price Calculator
- Enter each purchase as a number of shares and the price you paid. Add more rows with Add a purchase.
- Add your commission rates if you pay them. The average price, total cost and average including fees update as you type.
- Enter the current price to see your profit or loss if you sold now and the break-even sell price.
- To average down or up, enter a target average and the price of your next buy to get the number of shares needed. Or enter shares to add to see your new average.
Average price formula
Your average price is total cost ÷ total shares. Buy 10 shares at 70 and 20 at 60 and you have paid 1,900 for 30 shares, so the average is 63.33. It is not the simple average of 70 and 60 (65), because you bought more shares at the lower price.
Averaging down: how far does the average move?
Holding 10 shares at 70 and buying more at 60:
| Shares added | Total shares | New average |
|---|---|---|
| 5 | 15 | 66.67 |
| 10 | 20 | 65.00 |
| 20 | 30 | 63.33 |
| 30 | 40 | 62.50 |
| 50 | 60 | 61.67 |
Five times as many extra shares only takes the average from 65 to 61.67, because it can never fall below the 60 you are buying at.
Shares needed for a target average
Shares needed = shares held × (current average − target) ÷ (target − next buy price). The same formula works for averaging up: if you buy above your average, it tells you how many shares you can add before the average reaches your limit.
To see the real return on a completed trade after fees, use the Stock Profit Calculator.
Frequently asked questions
How is the average price worked out?
Add up the cost of every purchase (shares × price) and divide by the total number of shares. Buying 10 shares at 70 and 20 shares at 60 costs 1,900 for 30 shares, an average of 63.33, not the simple average of the two prices.
How many shares do I need to buy to reach a target average?
Shares needed = shares held × (current average − target) ÷ (target − next buy price). The calculator does this for you and rounds up to whole shares.
Can I average below the price of my next buy?
No. A new average always lands between your current average and the price you buy at, so a target below the next buy price cannot be reached.
Does averaging down reduce my loss?
It lowers your loss as a percentage and your break-even price, but because you put more money in, the loss in money terms grows if the price keeps falling.
What does average including fees mean?
Your total cost including buy commissions divided by the number of shares. It is the price you actually paid per share.
Can I share my calculation?
Copy link to this calculation copies an address with your purchases and settings in it.