Calculate your new average stock price after buying additional shares. See total cost, shares, break-even price, and averaging-down scenarios instantly.
Add the live price to see unrealized profit or loss, or a target average to find out how many shares it would take.
Averaging down increases your position in a falling stock. This tool does the arithmetic; it is not a recommendation to buy.
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Buy more of a stock you already own and your average cost per share moves. This calculator gives you the new average, the total you have invested, and the price at which the whole position breaks even — with brokerage fees included, and a table showing what different buy sizes would do to that average.
Your average share price — also called average cost or cost basis per share — is everything you have paid for a holding divided by the number of shares you own. It is not the average of the prices you paid: a 500-share buy moves it far more than a 10-share buy, because it is weighted by the money involved. Buying below your average pulls it down (averaging down); buying above it pushes it up (averaging up).
Average share price
A holding has fallen and you are deciding how many shares it would take to bring your cost basis meaningfully lower.
Adding to a winner, and you want to know the new break-even before you buy.
You know the average you want; enter it and the calculator solves for the number of shares.
Reconciling several purchases of the same stock into the single per-share figure your records need.
The position is whole again the moment the market price reaches your average cost. Every decision about when to sell is measured from that line.
On a small buy a flat commission can add more to your cost per share than a few cents of price improvement saves you.
Cost basis is what gets subtracted from your proceeds to work out a capital gain, so the average you carry is the number the tax calculation starts from.
Doubling a position moves the average roughly four times as far as adding 25%. The scenario table shows exactly how far, before you commit.
Add up everything you have paid — each purchase’s shares times its price, plus fees — and divide by the total number of shares. For 100 shares at 150 and 50 more at 100: (15,000 + 5,000) ÷ 150 = 133.33 per share. It is a weighted average, so the bigger purchase pulls harder.
Buying more of a stock at a price below your current average, which lowers your cost per share. It reduces the price you need to break even, but it also puts more money into a position that has already fallen — the arithmetic improves while the risk concentrates.
It lowers your break-even, which is arithmetic and always true. Whether it pays depends entirely on whether the stock recovers. Averaging into a business whose situation is deteriorating increases the loss; the calculator can tell you the new average, not whether the company is sound.
Cost basis is the total you have paid for the holding, including commissions. Average share price is that total divided by your share count — cost basis per share. Tax reporting generally uses the total; brokers usually display the per-share figure.
Yes. Fees are part of what the shares cost you, so they belong in the basis and in the break-even. On a small trade a flat commission can move the average by more than the price difference you were trying to capture, which is why this calculator takes both a flat and a percentage fee.
Enter the average you are aiming for and the calculator solves for it directly. Note that the target has to sit between your current average and the price you are buying at — you cannot average down to below the price you are paying.