Stock Average Calculator
A stock average calculator works out your average cost per share when you have b
A stock average calculator works out your average cost per share when you have b
How to use Stock Average Calculator
- Enter the number of shares and the price per share for your first purchase.
- Click Add another buy and fill in the shares and price for each additional purchase at a different price.
- Read your average cost per share, and optionally enter the current price to see your gain or loss.
About Stock Average Calculator
A stock average calculator works out your average cost per share when you have bought the same stock at more than one price. Enter the number of shares and the price you paid for each purchase, and the tool adds up the total amount invested and divides it by the total number of shares. This is the weighted-average (dollar-cost) method brokers use to report cost basis, so it also shows your true break-even price after averaging down or up.
Add a row for every buy at a different price, and optionally enter the current market price to see your position's current value and unrealized gain or loss in both dollars and percent. Fractional shares and prices with cents are supported.
Everything runs entirely in your browser using plain JavaScript. Nothing you type is uploaded, saved, or sent anywhere. Results exclude brokerage commissions, fees, and taxes, and are for informational purposes only, not financial advice.
Frequently asked questions
- How is the average stock price calculated?
- It uses a weighted average: multiply the shares by the price for each buy to get the cost of that purchase, add up every purchase to get your total invested, then divide by the total number of shares. That gives the average cost per share, which is your break-even price before fees.
- Is this a simple average of the prices?
- No. A simple average of the prices you paid would be wrong unless you bought the same number of shares each time. This tool weights by quantity, so a buy of 100 shares counts more than a buy of 10 shares, which matches how your broker calculates cost basis.
- Does it account for fees, commissions, or taxes?
- No. The calculation is based only on the shares and prices you enter. Add any per-trade commission into the price if you want a more precise cost basis. It does not model taxes, so treat the result as an estimate, not tax or financial advice.
- Can I use it for averaging down or dollar-cost averaging?
- Yes. Add one row per purchase at each price. As you add lower-priced buys, the average cost per share drops (averaging down); higher-priced buys raise it. Enter a current price to see whether your combined position is up or down.
- Does it support fractional shares?
- Yes. You can enter decimals for both shares and price, so fractional-share purchases and prices with cents are handled correctly.
- Is my data private?
- Yes. The calculator runs 100% in your browser. Your share counts and prices are never uploaded, stored, or shared, and no sign-up is required.