Stock Average Calculator
Average down your cost basis
Enter each purchase to see your average cost per share, total invested, and optional gain or loss versus the current price.
Two purchases
Purchases
How the average was built
Versus current price
Unrealized result
Next check
See if this ticker is still in an advancing stage before averaging down further.
How it works
Step 1
Enter each purchase
Add the shares and price from every fill you want in the average, including an optional current quote to see gain or loss.
- Works for two lots or a longer buy history
- Runs in the browser with no wait
Step 2
Read the new cost basis
The result shows average cost per share, total shares, and total invested. If you add a current price, it also shows unrealized profit or loss.
- Same weighted-average formula used by brokers
- Average cost, shares, and total invested
- Link to Stage Analysis before adding more risk
How a stock average down calculator works
Average cost is a weighted average: total dollars spent divided by total shares owned. Buying more shares below the current average lowers that average; buying above it raises it.
A cheaper average does not change the stock’s trend. Use the result as a cost-basis number, then check Stage Analysis if you are deciding whether to add to the position.
Results are calculated from the numbers you enter—not generated by AI and not pulled from a brokerage account. This tool is not investment advice.
Frequently asked questions
How do I calculate my average stock price?
Multiply shares by purchase price for each lot, add those costs, then divide by total shares. This calculator does that math as soon as you enter purchases.
What is an average down calculator?
An average-down calculator shows the new cost basis after you buy more shares at a lower price. If you owned 100 shares at $50 and buy 50 at $40, the average becomes $46.67.
Is averaging down the same as dollar-cost averaging?
Not exactly. Dollar-cost averaging is a planned schedule of buys. Averaging down is buying more after a decline to lower the average cost of shares you already own.
Should I average down on a falling stock?
A lower average price is not automatically a better investment. After you have the cost basis, check the stock’s market stage on the InvestorWaves Stage Analysis tool before adding risk.
Is this investment advice?
No. The tool is for educational and informational use and does not recommend buying or selling a security.
Try a worked example