Stock Average Calculator
Work out your average buy price after several purchases of the same share.
About the Stock Average Calculator
List each purchase on its own line as quantity and price, for example “50 120”. The calculator gives your average cost per share, the total invested and, if you enter today's price, how far the whole position is up or down.
Your average cost is the total paid divided by the total shares, not the average of the prices. Buying more at a lower price (averaging down) lowers it, but also increases how much you have riding on the stock.
The formula
Average price = Σ(quantity × price) ÷ Σ quantity
Worked example
Bought 50 at 120, 30 at 105 and 40 at 98
- Total cost: 6,000 + 3,150 + 3,920 = 13,070 for 120 shares
- Average = 13,070 ÷ 120 = 108.92
- At a price of 100 the position is down 1,070 (−8.19%)
Things to keep in mind
- Charges aren't included unless you add them to the price of each purchase.
- Tax rules for which shares you sold first (FIFO, average cost) vary by country.
Questions people ask
Should brokerage be included?
For tax and true breakeven, yes: add charges to the cost.
Is averaging down a good idea?
Only if your reasons for owning the stock still hold.
Why isn't it the average of my prices?
Each price is weighted by how many shares you bought at it: (120 + 105 + 98) ÷ 3 = 107.67 is wrong here because you bought more at 120.