Stock Average Price Calculator
Weighted by shares, not by the number of buys.
Work out Stock Average Price. Weighted by shares, not by the number of buys. Names the misconception directly.
Comma separated. Must line up with the prices below.
Average price paid
19
100.00 shares for 1,900.00 total
The average is weighted by shares, not by the number of purchases. Buying 10 shares at 100 and 90 at 10 gives an average of 19, not the 55 you would get by averaging the two prices — and that distinction is the whole point of the page. Break-even is the average price. Below it you are down; above it you are up, before costs and tax. It is the honest reference point for a position built over several purchases, and it is what makes a paper loss feel different from a paper gain. Averaging down reduces the break-even price and increases the position size. Both of those are real, and whether it is a good idea depends entirely on why the price fell — the arithmetic here says nothing about that.
How the Stock Average Price Calculator works
Average purchase price across several buys, weighted by shares. Buying 10 at 100 and 90 at 10 averages 19, not 55 — and that distinction is what the page exists for.
Also known as: average price paid for shares · what is my break even price · averaging down calculator · cost basis across multiple buys
Not financial advice. This calculator is for planning and illustration, not financial advice. Real products carry fees, taxes, and terms it does not model. Confirm figures with your lender or a qualified adviser before committing.
Frequently asked questions
How do I calculate my average share price?
Total amount invested divided by total shares held. It is weighted by the size of each purchase, not by how many purchases you made.
What is my break-even price?
The average price paid, before dealing costs and tax. Below it the position is down; above it, up — regardless of how any individual purchase looks in isolation.
Is averaging down a good idea?
It lowers your break-even and increases your position size. Both are real, and whether it is wise depends entirely on why the price fell — arithmetic cannot answer that.
Does this match my broker's cost basis?
For simple purchases, usually. Brokers may use different accounting methods for partial sales — first in first out, or specific identification — which changes the basis of what remains.
Should I include dealing costs?
For a true cost basis, yes — add them to the purchase amounts. On small trades they can be a meaningful share of the cost and they are deductible against gains in most jurisdictions.
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