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Stock Average Price Calculator

Add each stock purchase with its share quantity, execution price, and transaction fee. The calculator weights each price by the shares bought, then estimates break-even and optional unrealized profit or loss from a current price you provide.

Your assumptions

Enter your numbers

Change the example values to model your own scenario. Calculations run in this browser.

Stock purchase transactions

Add each buy with its share count, price, and optional transaction fee.

Purchase 1
Purchase 2

Scenario estimate

Results

Find a weighted average stock cost basis across multiple purchases, with fixed transaction fees and optional unrealized profit or loss.

Weighted average cost per share$53.47
Total shares15
Total cost basis$802.00
Break-even price per share$53.47
Estimated unrealized profit or loss$23.00

Fractional shares are supported. This planning average is not a tax-lot determination.

Purchase prices and average cost

Each point uses the inputs above. Read the labeled units and series together; the table below gives the exact values.

  • Purchase price
  • Average cost
Purchase prices and average costUSD per share$0$15$30$45$60Buy 1 · Purchase price: $50.00Buy 2 · Purchase price: $60.00Buy 1 · Average cost: $53.47Buy 2 · Average cost: $53.47Buy 1Buy 2Purchase

Tab through points for exact values, or open the data table. The chart resizes to fit the available width.

Open data table (2 points)
Purchase prices and average cost · USD per share by Purchase
PurchasePurchase priceAverage cost
Buy 1$50.00$53.47
Buy 2$60.00$53.47
View 2 rows of calculator details

Values use the assumptions entered above.

Purchase cost basis
PurchaseSharesPriceFeeCost basis
Buy 110$50.00$1.00$501.00
Buy 25$60.00$1.00$301.00

How to use this calculator

Add each stock purchase with its share quantity, execution price, and transaction fee. The calculator weights each price by the shares bought, then estimates break-even and optional unrealized profit or loss from a current price you provide.

How the calculation works

Total shares = sum of quantities. Cost basis = sum of (quantity × purchase price + purchase fee). Average cost per share = cost basis ÷ total shares; estimated break-even equals that cost per share before any sale fee.

Worked example

Buying 2.5 shares at $10 with a $1 fee and 1.5 shares at $20 with a $1 fee gives 4 shares and $57 of modeled cost basis, or $14.25 per share.

Assumptions and limitations

Uses your entered executions and fixed fees. It is a planning average, not a broker statement or tax-lot method; taxes, corporate actions, and sale fees are not included in this average.

Official sources and further reading

Frequently asked questions

Why is this a weighted average?

Each purchase contributes its actual share quantity and cost. A larger share purchase has more effect than a smaller one.

Does the average determine my tax basis?

No. Tax reporting can depend on tax-lot identification, account records, and applicable rules. Use your broker records or qualified tax guidance.

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Educational scenario only. This calculator does not provide individualized investment, tax, or legal advice. Confirm transaction records, tax treatment, and investment terms with the relevant official documents or qualified professionals.