Average Down Calculator
See your new average cost after buying more, or how many shares you need to reach a target average — with commissions, tax and break-even price.
sh
sh
How many shares at the current price bring your average to this value.
Fees & tax (defaults: Korea 0.015% + 0.20% sell tax / US 0.25%)
%
%
%
Commissions vary by broker. Capital-gains tax depends on your country and holding period, so it is not included.
Results are for reference only and are not a recommendation to buy or sell. Your inputs never leave this browser.
Averaging down: what to know
- How to Calculate Your Average Cost After Averaging DownThe weighted-average formula for your new cost per share after buying more, worked by hand in a table, plus how commissions change it.
- How Many Shares to Reach a Target Average CostSolve the average cost formula backwards to find the shares needed for a target average, and see when the target is impossible.
- Commissions, Taxes and Your Break-even PriceHow commissions and sell fees set your true break-even price, plus US capital gains tax, tax lots and the wash-sale rule when averaging down.
- The Risks of Averaging DownAveraging down lowers your cost per share but raises the money at risk. Losses if the price keeps falling, opportunity cost and concentration.
- Averaging Down Calculator FAQCommon questions: the average cost formula, why a target can be impossible, default fees, why capital gains tax is excluded, and your privacy.
- Does Selling Shares Change Your Average Cost?Worked numbers showing why a partial sale leaves average cost unchanged, how to find realized gain with fees, and how FIFO and specific lots differ.