Average Stock Price & Cost Basis Calculator
Calculate weighted average purchase price, total shares and total invested amount across multiple purchase lots.
Private by design. Inputs and calculations stay in this browser tab. No financial or property values are uploaded.
Stock Average Calculator
Weighted average cost equals total dollars invested across purchase lots divided by total shares acquired.
Broker tax cost basis can include fees, corporate actions and lot-specific rules not represented here.
Sensitivity analysis
Scenario lab
Changes only Price – purchase 2 while holding the other assumptions constant.
Primary result: 45
Primary result: 45
Primary result: 45
Primary result: 45
Primary result: 45
This calculator is an educational planning tool. Verify financing, tax, legal, investment and accounting decisions using the authoritative documents and professionals that apply to your situation.
Calculate weighted average purchase price, total shares and total invested amount across multiple purchase lots. OpenFileTools exposes the inputs, formulas and scenario effects so the estimate remains auditable.
Model the decision with explicit assumptions
- Enter realistic assumptions instead of best-case values.
- Use the scenario lab to see which assumption changes the result most.
- Verify taxes, rates, fees, legal rules and market inputs from authoritative sources before making a real decision.
How OpenFileTools processes it
Local processing, explicit choices.
The browser evaluates the published calculation from your inputs and recomputes a bounded sensitivity range around the selected scenario variable. No external market feed or hidden scoring service is called.
Questions, answered.
Is my data uploaded?
No. Batch 3 workbooks, trackers and calculators run locally in this browser tab and generate downloads on your device.
Are the results official advice?
No. These tools are planning and analysis aids. Verify important academic, financial, tax, legal, lending, employment or investment decisions with the relevant authoritative source or professional.
Related guide
Read the related guide