Quick guide
How to use this calculator
- Gather Layer A units, Layer A unit cost, Layer B units, Layer B unit cost, and Units sold for the same business scenario before calculating.
- Use one SKU scope, valuation basis, and reporting cut-off; physical counts and accounting quantities may require a separate reconciliation.
- Apply the displayed weighted average inventory result to the stated decision only after checking every entered assumption.
Calculation method
Calculation method
Average unit cost = total layer cost ÷ total units; COGS = units sold × average cost.
The calculation uses these named inputs: Layer A units, Layer A unit cost, Layer B units, Layer B unit cost, and Units sold. No market rate, benchmark, tax rule, or accounting classification is inserted automatically.
Fixed-decimal arithmetic remains exact through display unless a result is explicitly labelled approximate, such as a square-root inventory quantity.
Inventory accounting and stock control
Where the Weighted Average Inventory Calculator helps
Value inventory using a weighted average unit cost from two entered layers.
Use the result to reconcile entered stock movements or apply the explicitly named inventory-cost convention.
- Review a stock-count variance
- Reconcile beginning stock, movements, and ending stock
- Compare an entered inventory-cost method across the same transactions
Interpretation check
How to audit the result
Recalculate the scenario when any of these inputs changes: Layer A units, Layer A unit cost, Layer B units, Layer B unit cost, and Units sold.
Keep this formula beside the result: Average unit cost = total layer cost ÷ total units; COGS = units sold × average cost. Then compare the output with the source records and the calculator-specific assumption below.
- Confirm that all amounts use one currency and reporting period.
- Check that rates, counts, and quantities describe the same population or transaction set.
- Save the entered assumptions with the decision; the result alone is not reproducible evidence.
Worked example
Worked example
100 units at 10 and 100 at 12 average 11; selling 150 gives COGS 1,650.00.
Average unit cost = total layer cost ÷ total units; COGS = units sold × average cost.
Supported inputs
Precision and limits
Visible input limits
Fixed decimals accept up to 30 digits and 12 decimal places and are capped at an absolute value of 1e12 per input. Rates are capped at 1000%; percentage shares and method-specific domains may be narrower.
International scope
No currency, tax jurisdiction, accounting framework, payroll rule, marketplace fee schedule, financing term, or industry benchmark is selected automatically.
Decision boundary
Use the result to reconcile entered stock movements or apply the explicitly named inventory-cost convention. Results remain arithmetic scenarios, not accounting records, forecasts, valuations, legal interpretations, professional advice, or recommendations.
Calculator-specific assumptions
This is a scenario from visitor-entered values. Keep currencies, periods, accounting classifications, and operating definitions consistent. It is not accounting, tax, legal, investment, or business advice.