Investing
Stock Average Calculator
Buying more of a stock at a different price changes your average cost. Enter your two purchases — shares and price each — to see your blended average cost per share, total shares held, and total amount invested (your cost basis).
Average cost per share
$43.33
Your blended cost basis across both purchases.
- Total shares
- 150
- Total invested
- $6,500
- Break-even price
- $43.33
The price you need to sell at to break even.
How this calculator works
Total invested = shares₁ × price₁ + shares₂ × price₂. Average cost = total invested ÷ total shares. The break-even price equals your average cost (before fees and taxes).
Covers two purchase lots; for more, add each lot's cost and shares the same way. It doesn't include trading commissions or taxes, which slightly raise your true break-even. Cost basis for tax purposes may also be affected by dividends and wash-sale rules.
Try an example
Frequently asked questions
How do I calculate my average stock cost?
Add up the total amount you paid across all purchases, then divide by the total number of shares. Buying 100 shares at $50 ($5,000) and 50 at $30 ($1,500) is $6,500 for 150 shares — an average cost of about $43.33 per share. This becomes your break-even price.
What is 'averaging down'?
Buying more shares of a stock after its price has fallen, which lowers your average cost per share. It reduces the price you need to break even, but it also increases your position in a losing investment — so it only pays off if the stock recovers. Averaging down on a declining company can deepen losses.
What is cost basis and why does it matter?
Cost basis is the total amount you paid for an investment, including any fees — the figure used to calculate your capital gain or loss when you sell. A lower average cost basis means a larger taxable gain (or smaller loss). Brokerages track it for you, but it's worth understanding for tax planning.
Should I average down or cut my losses?
It depends on why the price fell. If your original reason to own the stock still holds and the drop is temporary, averaging down can be sound. If the company's fundamentals have deteriorated, adding more money often just increases the loss — the classic 'throwing good money after bad.' Judge the business, not just the price.
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Disclaimer: DayCents provides this calculator for educational purposes only. Results are estimates based on your inputs and the stated assumptions — they are not financial advice, a quote, or an offer of credit. Consult a qualified financial professional before making major money decisions.