Stock Average Calculator

Multiply each purchase's share count by its price, add those amounts to get total invested, then divide by the total number of shares. For 120 shares at $85 plus 180 at $62: ($10,200 + $11,160) ÷ 300 = $71.20. Do not simply average the two prices — that gives $73.50 and is wrong whenever your lot sizes differ.

Because a weighted average accounts for how many shares each price applied to. If most of your shares were bought cheaply, your true average sits closer to the low price. Averaging the prices treats a 10-share purchase and a 1,000-share purchase as equally important, which they plainly are not.

Before costs, yes — at that price you would sell for exactly what you paid. In practice your true break-even is slightly higher because of any brokerage on the way in and out, and because a gain may be taxable. In a taxable account, breaking even on price can still leave you marginally behind after fees.

Only if you would buy the stock today at today's price on its own merits, ignoring your existing holding. Averaging down lowers your break-even but increases the capital exposed and concentrates your portfolio. If the price fell because the business deteriorated, adding shares makes the loss larger. The lower average is a mathematical consequence, not evidence of a good decision.

Less than most people expect, and with sharply diminishing returns. On 100 shares bought at $100 now trading at $70: adding 100 shares cuts the required recovery from 42.9% to 21.4%; adding 400 shares gets it to 8.6% but commits $38,000 instead of $10,000. The benefit flattens while the capital at risk keeps rising linearly.

Combine lots that were bought at the same or very similar prices, entering their total shares against that price. If your prices are all different, calculate the weighted average in two passes: average the first four lots, then treat that result as one lot with its combined share count and add the rest. The maths is unaffected by grouping.

Your average cost per share does not change by selling — only the number of shares you hold does. What changes is your tax position, because which lots you sold determines the gain realized. If you sell and later buy again, run the calculation fresh on the lots you still own.

For an exact cost basis, yes — fees are part of what the shares cost you. Either add each lot's fee into its cost, or divide total fees by total shares and add that to the average. Since most major US brokers charge $0 commission on stock trades, this is often immaterial, but it matters on platforms with percentage-based charges.

Usually not for individual stocks. The IRS default is FIFO — oldest shares sold first — and you may instead use specific identification if you designate lots at the time of sale. Average cost is generally permitted only for mutual funds and most ETFs. So this figure is your economic average, which may or may not equal your reportable tax basis.

Dollar-cost averaging is investing a fixed amount on a regular schedule regardless of price — a systematic habit that removes timing decisions. Averaging down is a discretionary choice to add to a specific position because it fell. The first is a plan; the second is a judgement call about one holding, and it deserves much more scrutiny.

Because you bought more shares at that price. The average is always pulled toward whichever lot holds the most shares. Buy 40 at $150 and 25 at $215 and your average lands at the cheaper end of the range, since the larger lot carries more weight in the calculation.

In principle yes — each reinvestment is a purchase at that day's price, so it is another lot. In practice a long-running reinvestment plan creates far too many small lots to enter by hand, which is exactly why the average cost method exists for funds. Your broker will normally track and report this for you.