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Average purchase price: What have your shares cost?

If you buy the same stock several times, you have rarely paid the same price each time. The average purchase price combines the trades into one cost price per share.

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Applies to the amounts in this calculator.

The number of shares in each purchase, in order.

Separate the values with semicolons or spaces, for example 10; 20; 30.

The price at each purchase, in the same order.

EUR

Separate the values with semicolons or spaces, for example 10; 20; 30.

The brokerage on each purchase, in the same order. Enter 0 for a purchase without brokerage.

EUR

Separate the values with semicolons or spaces, for example 10; 20; 30.

All purchases must be in the same stock and currency. This is not a tax calculation.

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Worked example
  • Number of shares per purchase: 10; 20
  • Price per purchase: 100.00 EUR; 130.00 EUR
  • Brokerage per purchase: 29.00 EUR; 29.00 EUR

Result

Total number of shares

30

Amount invested

3,658 EUR

Average purchase price with brokerage

122 EUR

Average price without brokerage

120 EUR

Working

  1. quantity = Σq
    10 + 20 = 30
  2. invested = Σ(q × P + k)
    (10 × 100.00 EUR + 29.00 EUR) + (20 × 130.00 EUR + 29.00 EUR) = 3,658.00 EUR
  3. average price with brokerage = invested / quantity
    3,658.00 EUR / 30 = 121.93 EUR
  4. average price without brokerage = Σ(q × P) / quantity
    (10 × 100.00 EUR + 20 × 130.00 EUR) / 30 = 120.00 EUR

Add each purchase with the number of shares, price and brokerage. The calculator shows the total number, the amount you invested and the average price including purchase costs.

The number of shares determines the weight

The formula is average purchase price = total cost of purchase / total number of shares. A large purchase therefore counts more than a small one.

You cannot just add the prices together and divide by the number of trades, unless you bought the same number of shares each time and ignore fees.

Example with two purchases

First you buy 10 shares at 100. Later you buy 20 shares at 130. You have now paid 3,600 for 30 shares. The average price is 120 before brokerage.

With 29 in brokerage on each trade, the cost of purchase is 3,658 and the cost price about 121.93 per share.

Use the cost price to understand your holding

Compare the average price with a current or planned sale price to see the price difference. A lower average price after a new purchase does not in itself mean the investment has improved; you have also invested more money.

All trades must concern the same share class and currency. If the stock has been split, historical quantities and prices must be converted to the same basis. Partial sales and special corporate events require a more detailed calculation.

The calculated cost price can be used further in the stock return calculator, which also includes brokerage on the sale and dividends.