Calculator guide
Calculate a weighted average share cost after another purchase. Use the explicitly labelled inputs below; rates, dimensions, and costs are assumptions, not live quotes.
Formula or method
Weighted average share cost = (existing shares × existing price + new shares × new price) ÷ total shares.
How to use this calculator
- Set Existing Shares (shares). The interface starts with 100; replace it with the value for your scenario.
- Set Existing Average Price. The interface starts with 50; replace it with the value for your scenario.
- Set New Shares Purchased (shares). The interface starts with 50; replace it with the value for your scenario.
- Set New Purchase Price. The interface starts with 40; replace it with the value for your scenario.
- Compare the result with the worked example, then vary one assumption at a time so you can see what changes.
Worked example
Enter Existing Shares = 100 shares; Existing Average Price = 50; New Shares Purchased = 50 shares; New Purchase Price = 40. With those assumptions, the calculator gives Total Shares: 150; Total Cost Basis: $7,000.00; New Average Cost: $46.67. These outputs are calculated from the same implementation as the interactive tool.
Understanding the result
In this example, Total Shares is 150. Total Cost Basis is $7,000.00. Estimates exclude charges and rules not represented by the inputs. Rates and prices are assumptions; results are not a quote or guaranteed return.
Limitations and assumptions
- Estimates exclude charges and rules not represented by the inputs. Rates and prices are assumptions; results are not a quote or guaranteed return.
- The worked example demonstrates the stated assumptions, not a recommendation about your personal circumstances.
Frequently asked questions
Which inputs should I check first?
For Stock Average Cost Calculator, check Existing Shares, Existing Average Price, New Shares Purchased, New Purchase Price. Keep the displayed units and select options consistent; do not treat default values as recommendations.
Why might my result differ from another tool?
Compare the other tool's stock average cost calculator method, input units, rounding and assumptions. A matching title does not guarantee that both tools answer the same question.
Does a linked reference certify this result?
No. A reference can explain a formula or provide background for Stock Average Cost Calculator, but it does not endorse this website, validate personal inputs or establish professional suitability.
Sources
Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.