Calculate the average cost per share across multiple buy transactions. Find your break-even price and total position value.
How Stock Average Price Works
When you buy shares of the same stock at different prices, your average cost basis is the total amount invested divided by the total number of shares. This weighted average determines your break-even point — the price at which you neither gain nor lose money.
Average Price = Total Cost / Total Shares
Total Cost = Sum of (Price x Quantity) for each purchase
Break-Even Price = Average Price (before fees)
Frequently Asked Questions
Average cost basis is the weighted average price you paid per share across all your purchases. If you bought 100 shares at $50 and 200 shares at $40, your average cost is (100x50 + 200x40) / 300 = $43.33 per share. This is important for determining your profit or loss when selling.
Averaging down means buying more shares when the price drops, which lowers your overall average cost. For example, buying 100 shares at $50, then 100 more at $30, gives an average of $40. If the stock recovers to $45, you profit $5/share instead of still being down $5/share from your original purchase.
This calculator shows the raw average price without brokerage fees or commissions. Most modern brokers charge zero commissions for stock trades. If you do pay fees, add them to your total cost for a more accurate cost basis.
Your cost basis determines your capital gain or loss when you sell. The IRS allows different methods: average cost (mutual funds), FIFO (first in, first out), LIFO (last in, first out), or specific identification. The method you choose can significantly impact your tax bill.
Buying at regular intervals regardless of price naturally averages your cost basis and reduces the risk of buying everything at a peak. Try our DCA Calculator to project returns.