Averaging Down Calculator FAQ
Common questions about averaging down and how the avgdown calculator works. Results are for reference only and are not a recommendation to buy or sell.
What does averaging down mean?
Averaging down means buying more shares of a stock you already own at a price below your average cost, which lowers your average cost per share. Buying more above your average raises it and is sometimes called averaging up. The calculator handles both directions.
How do I calculate my new average cost?
New average = (old average × shares owned + buy price × new shares) ÷ (shares owned + new shares). For example, 40 shares at $120 plus 40 shares at $90 gives ($4,800 + $3,600) ÷ 80 = $105. The formula guide walks through a full table.
Why does the calculator say my target average is impossible?
Your new average always lands between your old average and the price you buy at. If the current price is at or above your target, buying more at that price can only pull your average toward the price, never down to the target. With the stock at $118, for example, no number of shares gets a $120 average down to $115. See the target average guide for the math.
What fees does the calculator assume?
The US preset uses a 0.25% commission on buys and sells and no sell tax, which matches what many non-US brokers charge for US shares. Many US brokers charge $0, so you can set both commissions to 0 under “Fees & tax.” The Korean preset uses 0.015% commissions and a 0.20% sell tax.
Why isn't capital gains tax included?
Capital gains tax depends on your income, how long you held each lot, your state and every other trade you make in the year, so a single-position calculator cannot compute it accurately. The break-even price covers commissions and sell taxes only. The fees and taxes guide explains the main rules, including wash sales.
Are my numbers stored or sent anywhere?
No. All calculations run in your browser and nothing you type is sent to a server. If you press “Copy result link,” your numbers are placed in the page address, and they only go to someone else if you share that link.
Why is my broker's average slightly different?
Brokers differ in whether they include commissions in the average and in how they round. The calculator shows both the plain average and the average including fees, so you can compare with whichever your broker uses.