Find your true cost basis across every buy — instantly.
Buy Lots
Results — AAPL
Unrealized Gain
$468.75
Lot Breakdown
| # | Price | Shares | Cost | Weight |
|---|---|---|---|---|
| 1 | $142.50 | 10 | $1,425.00 | 35.3% |
| 2 | $128.75 | 15 | $1,931.25 | 47.9% |
| 3 | $135.00 | 5 | $675.00 | 16.7% |
| Total | $134.375avg | 30 | $4,031.25 | 100% |
How It Works
The Stock Average Calculator helps investors find their true average cost basis after purchasing shares at different prices over time. Enter each buy lot — price per share and quantity — and instantly see your blended average cost, total invested, break-even price, and unrealized gain or loss based on the current market price. Essential for dollar-cost averaging strategies.
Average cost basis = total amount invested ÷ total shares purchased. For example, buying 10 shares at $140 and 20 shares at $130 gives a total cost of $4,000 and 30 shares, so your average cost is $133.33 per share.
The break-even price is the average cost basis — the price per share at which you neither gain nor lose money if you sell. If the current price is above this, you're in profit; below it, you're at a loss.
Buying more shares at a lower price reduces your average cost basis, meaning the stock needs less of a recovery to become profitable. However, averaging down concentrates more capital in a single position, which increases risk if the stock continues to fall.
Unrealized profit and loss is the gain or loss on shares you still hold, calculated as (current price − average cost) × total shares. It becomes 'realized' only when you sell. This calculator shows unrealized P&L when you enter a current market price.