Average Cost Calculator (Average Price After a Second Purchase)
Average price per share after buying more, the total invested, the gain or loss at the current price and the price needed to break even after fees.
Results
What this tool does
When you buy the same share at two prices, your average cost is the weighted average: total spent divided by total shares, so the bigger purchase pulls the average further. Buying 100 shares at 50 and 50 at 40 gives an average of 46.67, not 45. That average is only the break-even before fees, so costs for buying and selling raise the price you need. Averaging does not change what the shares are worth today, it only changes your cost, and it raises the money you have at risk. Tax rules for working out cost basis differ from country to country.
Formula
average price = (q₁p₁ + q₂p₂) ÷ (q₁ + q₂) · break-even price = (invested + fees) ÷ shares
Variables
| Symbol | Meaning | Unit |
|---|---|---|
q1 | Shares in the first purchase | — |
p1 | Price per share, first purchase | — |
q2 | Shares in the second purchase | — |
p2 | Price per share, second purchase | — |
cp | Current price per share | — |
fe | Total fees (buying and selling) | — |
AV | Average price per share | — |
TS | Shares held in total | — |
TI | Total invested (before fees) | — |
GL | Gain or loss at the current price, after fees | — |
GP | As a share of the money invested | % |
BE | Price needed to break even after fees | — |
Worked example
- Shares in the first purchase100
- Price per share, first purchase50
- Shares in the second purchase50
- Price per share, second purchase40
- Current price per share45
- Total fees (buying and selling)0
- Average price per share46.6667
- Shares held in total150.00
- Total invested (before fees)7000.00
- Gain or loss at the current price, after fees-250.00
- As a share of the money invested-3.57 %
- Price needed to break even after fees46.6667
Limitations
- This is an informational calculator, not personalised financial advice. Rates, fees, taxes and contract conditions vary between institutions and countries.
- The tool works with whatever currency you use for the inputs; it does not convert between currencies.