Stock Average Calculator
Average cost per share across buys, profit or loss, and shares to reach a target.
About this tool
List each purchase with shares, price and fees. The tool shows average cost per share, total shares and invested, value and profit or loss at the current price, and the break-even price. The second section works out how many shares to buy at a given price to bring the average to a target.
Average cost, break-even and averaging down
Your average price is total spent including fees divided by total shares โ 50 shares at 120 plus 30 at 95, with 5 fees on each, average 110.75. It is your break-even, the cost basis brokers report, and the reference point for every โam I up or downโ question. Averaging down means buying more at a lower price to bring that average closer to the current price, and the target calculator solves (cost + n ร price) รท (shares + n) = target for n. It is useful arithmetic and a risky habit: it lowers the break-even but increases your exposure to a position that is falling, which is a judgement no calculator should make for you. The same maths works for crypto, ETFs and funds. Tax rules for cost basis โ first-in-first-out, share pooling, wash-sale rules โ differ by country and are not modelled. The ROI calculator compares investments, the percentage calculator handles quick price changes, the CAGR calculator annualises a holding, and Mean, median and mode: which average to use, and when the mean lies explains why a weighted average is used. General information, not investment advice.
Frequently asked questions
How do I calculate my average share price?
Add up everything you paid, including fees, and divide by the total number of shares. 50 ร 120 + 30 ร 95 + 10 in fees = 8,860 for 80 shares, an average of 110.75.
How many shares do I need to buy to lower my average?
Use the target section: enter the target average and the price you would buy at. It solves n = (total cost โ target ร shares) รท (target โ buy price).
Should I include brokerage fees?
Yes โ fees are part of what each share cost you, so including them gives the true break-even price.
Is my portfolio stored?
No. The figures stay in this browser tab and are not saved or sent.