This average down calculator takes the position you hold now, then the buy you are planning. You get your new average price per share, how far your average moves, and your new totals — with the sum shown using your own numbers.
Averaging down means adding to a position you already hold at a price below the average you paid. The new average is still a weighted average — the same arithmetic used everywhere on this site — with the buy you are planning counted in as one more purchase.
New average = (shares you hold × average you paid + shares you are buying × price of the buy) ÷ (shares you hold + shares you are buying)
The first bracket is the money in; the bottom line is everything you would own afterwards. Type your figures in above and the page prints that same sum with your own numbers under the result.
Worked example: you hold 100 shares at $50 and 50 shares at $60, so your average is 53.3333 across 150 shares. The stock is down to $45 and you buy 200 more at that price. Your new cost is 8,000 + 200×45 = 17,000 across 150 + 200 = 350 shares, giving a new average of 48.5714 — a fall of 4.7619, or 8.92%.
Rounding: every figure on this page is rounded down, never up — the same rule as the rest of the site. Prices are shown to four decimals and amounts to two. The change is worked out from the two averages exactly as they are shown on screen, so the numbers you read add up.
If the price you plan to pay is above your current average, the average goes up instead of down. The page says so rather than assuming otherwise.
This is an average down calculator for one position at a time. It uses only the share counts and prices per share you type in.
The result is what your average price per share would become, not what you should buy. It is arithmetic, not advice. If you want a commission folded in, add it to the price per share of that buy before typing it in. Amounts are shown in whatever currency you typed; no exchange rate is applied anywhere.
Averaging down moves your average closer to the current price. It also makes the position bigger. If the price keeps falling, you are now holding more of it — a lower average, and a larger amount exposed to the fall.
That is why the drop and the new totals are shown side by side here: the fall in your average and the rise in your cost and share count are one decision, not two, and both are on the screen at once.
One decision, two directions: the average moves down 4.7619 while the position adds 200 shares and 9,000.00. At 40.00 the smaller position would be down 2,000.00 and the larger one 3,000.00, worked on the example prices above.
Nothing on this page tells you to average down, or that you should buy any amount. It works the arithmetic out if you decide to.
A buy below your average can only move the average into the space between the two prices. It lands somewhere between the average you paid and the price of this buy, and it never reaches the price of this buy, however many shares you add. On the example above that space is 53.3333 down to 45.00, a ceiling of 8.3333, and no amount of money buys all of it.
How much of that ceiling a buy takes is fixed by one fraction: the shares you are buying, over everything you would hold afterwards. A buy of Q shares against S shares already held takes Q / (S + Q) of the ceiling, so the fall is the ceiling times that fraction. With 150 shares held, 200 more takes 200 / 350 = 57.1428% of it, 400 takes 72.7272%, and 800 takes 84.2105%. The average after each falls 4.7619, 6.0606 and 7.0176, and every one of them is still above 45.00.
That fraction is also why the money stops working as hard. The first 200 shares cost 9,000.00 and buy 4.7619 of fall, which is 0.5291 of fall per 1,000.00. The next 200 shares cost another 9,000.00 and buy 1.2987 more, which is 0.1443 per 1,000.00, under a third of the rate before it. The 400 after that cost 18,000.00 and buy 0.9570 more, which is 0.0531 per 1,000.00. Same share, same price, same ceiling: the only thing that moved is how much of the ceiling is left to buy.
Named the other way round, the share count for a given share of the ceiling is S times that share, over what is left of it. To take half of the ceiling needs 150 shares, to take three quarters needs 450, and to take nine tenths needs 1,350. The last tenth of the ceiling is the most expensive part of it, and it is the part nobody reaches.
One ceiling, three buys, and the rate each one gets. Holding 150 shares at an average of 53.3333, buying at 45.00.
This is what the calculator above is already printing, read from the other end. Change the shares you plan to buy and watch the fall: it grows, it grows by less each time, and the ceiling it is growing towards was set by the price you typed, not by the size of the buy.
Yes. Stock average down calculator and share average down calculator are two ways of writing the same request — the same inputs and the same weighted average, giving one answer. They are one page here, not two.
That one tells you the average of the buys you have already made. This page adds a purchase that has not happened yet, so you can see what your average would become before you decide. If you only want the average of your past buys, use the calculator on the home page.
This page does not work that way round — it does not take a target and return a share count. What it does is let you try a figure: enter the shares and price you are considering, read the new average, then adjust the share count until the average sits where you want it. Two or three tries usually gets you there.
Then the average rises. The label on the result changes from Average lowered by to Average raised by, and the figure tells you by how much. The page does not assume you are averaging down.
Yes. Add a row for every buy that makes up the position, using + Add purchase, and remove a row with the × on it. That way the average you start from is the real one, rather than a single blended figure you typed in.
The page counts only what you typed: the buys that make up the position, plus the one you are planning. A broker's average usually carries commissions, and it moves when a sale, a dividend or a corporate action is booked, so a gap between the two figures is a gap in what each side counted. The only arithmetic here is the weighted average printed under the result.
Yes on the phone: the fields fall into one column on a narrow screen, and the results keep inside the width of the page. There is nothing to install and no account to open — no sign-up, no pop-up, no email — because the whole sum is worked out in your browser and the figures you type are never sent anywhere.
Multiply each purchase by its own share count, add the results, and divide by the total shares: (shares x price, summed) over (shares, summed). That is the whole of it, and it is what the weighted average on this page prints under the result. Two buys, 100 shares at 50.00 and 50 at 60.00, give (5,000.00 + 3,000.00) over 150, which is 53.3333. The home page does this sum for the buys you have already made; this page adds the one you are still deciding on, so the answer is what your average would become.
This page is a calculator, not investment advice. Averaging down lowers your average price; it does not make a position safer. Contact: contact@stockavg.com