Weighted Average Costing Calculator

Track inventory value using weighted average purchase costs. Estimate COGS, ending inventory, and profit margins. Built for accountants needing faster, clearer stock valuation decisions.

Calculator Inputs


Purchase Batches

Purchase 1

Purchase 2

Purchase 3

Purchase 4

Purchase 5

Example Data Table

Item Units Unit Cost Extra Cost Total Cost
Beginning Inventory 120 $15.50 $0.00 $1,860.00
Purchase 1 80 $16.20 $45.00 $1,341.00
Purchase 2 100 $17.10 $60.00 $1,770.00
Purchase 3 60 $16.80 $30.00 $1,038.00
Units Sold 220 Used for COGS

Formula Used

Weighted Average Cost per Unit = Total Cost of Goods Available ÷ Total Units Available

COGS = Units Sold × Weighted Average Cost per Unit

Ending Inventory Value = Ending Units × Weighted Average Cost per Unit

Gross Profit = Sales Revenue − COGS

This calculator applies the periodic weighted average costing method. It pools beginning inventory and all entered purchases, then divides total available cost by total available units. Any extra landed cost entered for a batch is added to that batch before averaging.

How to Use This Calculator

  1. Enter beginning inventory units and cost per unit.
  2. Add up to five purchase batches with units, unit costs, and extra landed costs.
  3. Enter units sold for the period.
  4. Optionally enter selling price per unit to estimate revenue and gross profit.
  5. Click the calculate button to display results above the form.
  6. Use the CSV or PDF buttons to export the summary table.
  7. Review the chart to compare beginning inventory, purchases, COGS, ending inventory, and gross profit.

Frequently Asked Questions

1. What does weighted average costing mean?

Weighted average costing blends beginning inventory and purchase costs into one average unit cost. That average is then used to value COGS and ending inventory for the period.

2. Does this calculator use periodic or moving average?

This version uses periodic weighted average costing. It calculates one average after combining beginning inventory and all purchase batches entered for the selected period.

3. Can I include freight or landed costs?

Yes. Each purchase row includes an extra landed cost field. Use it for freight, duties, handling, or other direct costs tied to that purchase batch.

4. What happens if units sold are too high?

The page validates the entry and stops the calculation. Units sold cannot be greater than total units available from beginning stock plus purchases.

5. Can this estimate gross profit too?

Yes. Enter a selling price per unit and the calculator will estimate sales revenue, gross profit, and gross margin percentage using the calculated COGS.

6. Why does ending inventory change after new purchases?

New purchases change the pooled average cost. Since ending inventory is valued with that updated average, its value changes even if ending units remain the same.

7. Is this suitable for month-end close work?

It is useful for planning, review, and reconciliation. For final reporting, compare results with your ERP, accounting policy, and supporting inventory records.

8. Can I export the results after calculating?

Yes. After calculation, use the export buttons to save the summary as CSV or PDF. The export is based on the results table shown above the form.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.