Enter each amount, rate, and time period. The result updates automatically. Review the breakdown to compare the main estimate with the supporting planning figures.
Stock Average Cost Estimator
Combine two stock purchases to find the new average cost, total shares, and break-even price after fees.
Enter your assumptions
shares
$
shares
$
$
Result
—
Blended cost
Total shares—
Total cost basis—
Price change from old average—
Break-even value—
Average cost = (old shares × old price + new shares × new price + fees) ÷ total shares.
What the result means
The main result summarizes the calculation using your current inputs. The supporting figures show the components and useful comparisons.
This estimate is for planning and education. Investment returns, lending terms, taxes, fees, and actual cash flows can differ.
Combining 100 shares at $30 with 50 shares at $24 and $5 fees produces a blended cost near $28.03.
What assumptions does this calculator use?
It applies the values shown in the input panel and compounds or amortizes them at the stated interval.
Can I enter decimal values?
Yes. Decimal amounts and rates are supported where they are meaningful.
Are taxes and fees included?
Only when an input explicitly asks for them. Add outside costs separately when planning.
Why might an actual result differ?
Market returns, payment timing, rounding, taxes, and provider rules can change real outcomes.
How should I use the result?
Treat it as a planning estimate, then compare it with statements, quotes, or professional advice.