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Average Down Calculator

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Short answer

Your new average cost is everything you have paid divided by every share you will own. Buying 100 more shares at $35 on top of 100 bought at $50 brings the average to $42.50, so the stock needs to rise 21% instead of 43% for the position to break even. The catch is that the position is now twice as large, so another 20% drop costs twice as much. The calculator below shows all three numbers for your own position.

Run the numbers on your position

New average cost

$42.50

from $50.00, buying 100 shares

Rise needed to break even

21.4%

instead of 42.9% today

If it falls another 20%

-$1,400

instead of -$700 without adding

The position grows from $3,500 to $7,000. A lower average cost makes break-even closer, but only because more of your money now depends on this one stock.

Averaging down means buying more of a stock after its price has fallen, which lowers your average cost per share. This calculator works out the new average cost, how far the price has to rise before the whole position breaks even, and how much a further drop would cost once the position is larger. It runs in your browser and nothing you enter is stored. It does not tell you whether to buy; it shows what the purchase changes so you can decide with the numbers in front of you.

Link your portfolio and every change you make is scored against the portfolio you would have kept, in dollars, so you can see which decisions helped and which cost you.

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How the new average cost is calculated

Add what you paid for the shares you own to the amount you plan to invest, then divide by the total number of shares you will hold. The number of new shares is the amount invested divided by today’s price. The result is your new average cost per share, also called your cost basis per share.

Why break-even gets closer

The rise needed to break even is the gap between your average cost and today’s price. Buying at a lower price pulls the average down, so the gap shrinks. That is the appeal of averaging down, and it is real, but it comes from putting more money into the same stock rather than from any change in the stock itself.

What the larger position does to your risk

The red box shows what a further 20% fall would cost before and after the purchase. A bigger position means a bigger loss if the price keeps dropping. Many investors set a maximum position size in advance so that averaging down cannot quietly turn one holding into a concentrated bet.

Checking afterwards whether it helped

Whether the extra purchase was a good decision depends on what the stock does next, compared with not buying. Pure Benchmarks, our own product, scores every buy and sell in a connected account against the portfolio you would have had without it, so you can see in dollars whether averaging down helped.

Link your portfolio and every change you make is scored against the portfolio you would have kept, in dollars, so you can see which decisions helped and which cost you.

See Your Free Benchmark Report

Frequently asked questions

How do I calculate my average cost after buying more shares?

Add the total you paid for your existing shares to the cost of the new shares, then divide by the total number of shares. For example, 100 shares at $50 plus 100 shares at $35 is $8,500 for 200 shares, an average of $42.50.

How much do I need to buy to get my average cost to a target price?

Try different amounts in the calculator and watch the new average cost. The closer your target is to today’s price, the more shares you need, and the larger the position becomes.

Does averaging down reduce my loss?

It does not change the loss you already have. It lowers the price at which the whole position breaks even by adding more money to the same stock, which also makes any further drop more costly.

Is this calculator advice to buy more?

No. It shows the arithmetic of one purchase. Whether to buy depends on your own plan, and this page is information, not a recommendation about any holding.

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This page is an information baseline for comparison only. It is not investment advice and not a recommendation to buy, sell, replace, or transfer any specific asset, account, or firm. Past performance does not guarantee future results. All figures shown are illustrative.