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Average cost calculator: your new cost basis after buying more

Bought a stock more than once? Enter each purchase and see your total shares, the total you have invested and your weighted average cost per share.

How to use it

  1. Enter the shares and price of your first purchase.
  2. Add a second and third purchase if you have them.
  3. Read total shares, total invested and the average cost per share.
Average cost = total dollars invested รท total shares owned
Example. 100 shares at $50 plus 100 shares at $40: invested $9,000 for 200 shares, average cost $45.00.

About this calculator

Your average cost is the break-even price of the whole position. Buying more after a drop lowers it, which is why this is often called averaging down, but it also increases the money exposed to the same stock. The calculation ignores commissions and taxes. Decide the size of any add in advance using a position size calculator.

Frequently asked questions

How do you calculate average cost per share?
Add up the total dollars spent on all purchases and divide by the total number of shares.
Does averaging down lower my break-even?
Yes, the average cost falls, but the dollars at risk in the stock rise, and a stock can keep falling.
Do fees change the average cost?
Yes. Add commissions to the dollars invested to get an exact figure.

Planning an add to a position?

See SPY premarket levels: structure, key levels and catalysts in futures and SPY/QQQ terms, before the 9:30 ET open.

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Informational calculator for reference only. Outputs are arithmetic, not quotes, recommendations or trade signals. LiquidityLevels provides educational market commentary, not financial advice.