Average Price Stock Calculator
Enter each stock purchase lot (shares + buy price). The tool calculates your weighted average cost per share, total shares, and total investment. Optionally add your current market price to estimate unrealized gain/loss.
Tip: Leave unused rows blank. Only rows with valid shares and price are included.
What is an average price in stock investing?
Your average stock price (also called average cost basis per share) is the weighted cost you paid across multiple purchases of the same stock. It matters because it helps you quickly see whether your position is currently in profit or loss.
If you bought shares at different prices over time, the average is not a simple arithmetic mean of prices. It is weighted by how many shares were bought at each price.
Formula
Average Price = (Total Amount Invested + Fees) ÷ Total Shares Owned
- Total Amount Invested: Sum of (shares × buy price) for each purchase.
- Fees: Any commissions you want to include in cost basis.
- Total Shares Owned: Sum of all shares bought (minus sold shares if you want current basis).
Why use an average price stock calculator?
A calculator removes guesswork and helps you make cleaner decisions. Instead of eyeballing entries, you can instantly quantify your real break-even level.
- Track the true cost basis of your position
- Evaluate whether averaging down actually helped
- Set smarter exit targets and stop-loss levels
- Estimate unrealized P/L from current market price
How to use this calculator
Step 1: Add each buy transaction
For every purchase lot, enter the number of shares and the price paid. If you made recurring investments, include each order as a separate row.
Step 2: Include fees (optional)
If your broker charges commissions, add the total fees to get a more accurate cost basis. Many zero-commission brokers will leave this at 0.
Step 3: Add current price (optional)
If you enter the current stock price, the calculator estimates current market value, dollar gain/loss, and percentage return.
Example calculation
Suppose you bought:
- 10 shares at $100
- 15 shares at $90
- 5 shares at $120
Total shares = 30. Total cost = $2,950. Average price = $2,950 ÷ 30 = $98.33 per share (before fees).
If current price is $110, estimated gain = (30 × $110) − $2,950 = $350.
Dollar-cost averaging and average price
Many long-term investors use dollar-cost averaging (DCA), buying regularly regardless of market conditions. Over time, this naturally creates multiple purchase prices. The average price tells you where your blended entry point sits after all that accumulation.
This is especially useful in volatile stocks where price swings can be large between purchases.
Common mistakes to avoid
- Ignoring fees: Even small commissions can shift your true break-even price.
- Using a simple average of prices: Share count must weight each price.
- Forgetting sold shares: If you partially sold, your remaining basis may change depending on accounting method.
- Confusing average price with valuation: A low average cost does not automatically mean a stock is attractive now.
FAQ
Does average price change when I buy more shares?
Yes. Every new purchase updates total shares and total cost, which changes the weighted average price.
Can average price be lower than the lowest price I paid?
No. For only buy transactions, weighted average cost will always lie between your lowest and highest purchase prices.
Is average price the same as break-even?
It is your per-share cost basis. Break-even for a full exit may be slightly higher after considering selling fees, taxes, or spreads.
Final note
An average price stock calculator is a practical decision tool, not a prediction engine. Use it to understand your position clearly, then pair it with risk management, diversification, and a strategy that fits your time horizon.