Accounting Share · Inventory & purchasing
FIFO, LIFO and Weighted-Average Inventory Calculator
Compare periodic inventory cost-flow methods for a set of opening and purchase layers, with sales costed after all listed purchases.
The interactive calculator requires JavaScript. The formula and worked example below remain available.
01 / Enter your figures
Make the numbers yours.
Use one currency and consistent time periods. Amounts are shown in your input currency units; no currency conversion is performed.
02 / See the working
Your calculation
Enter your figures, then choose Calculate. Or load the worked example.
03 / Understand the method
Formula and method
COGS uses selected cost layers; Periodic weighted-average unit cost = Available cost ÷ Available units
Compare periodic inventory cost-flow methods for a set of opening and purchase layers, with sales costed after all listed purchases.
How to use this calculator
- Collect the figures for the same entity, currency and reporting period.
- Enter each input using its label and unit. For percentages, enter 15 to mean 15%.
- Choose Calculate, inspect the breakdown and compare the result with your assumptions.
- Change one input to explore a scenario. Recalculate after edits; display rounding does not round the underlying calculation.
Inputs at a glance
- Purchase quantities in order: Enter quantities from oldest to newest, including opening inventory as the first layer if applicable.
- Corresponding unit costs: Use the same number of entries as quantities.
- Total units sold after these purchases: A nonnegative numeric input in the units specified by the label.
Worked example
Follow one calculation.
- Purchase quantities in order
- 10,10
- Corresponding unit costs
- 4,6
- Total units sold after these purchases
- 10
- Calculated result
- 40
Load this example in the interactive form to inspect the intermediate amounts and the full schedule.
Assumptions and interpretation
This is a periodic model, not a perpetual transaction engine. LIFO is not permitted by IAS 2 under IFRS; permission under other frameworks must be checked.
The output is a model based on the figures entered. Check source records and use the accounting or contractual definitions relevant to your task before relying on a result.
Questions about this tool
What does the fifo, lifo and weighted-average inventory calculation measure?
Compare periodic inventory cost-flow methods for a set of opening and purchase layers, with sales costed after all listed purchases.
Which assumptions can change the result?
This is a periodic model, not a perpetual transaction engine. LIFO is not permitted by IAS 2 under IFRS; permission under other frameworks must be checked.
Why can displayed totals differ slightly from my spreadsheet?
Calculations use the unrounded input values. Only the display is rounded. Use four or six decimal places to inspect small differences, and check the timing, sign conventions and rounding policy in your spreadsheet.
Reference and further learning
Inventory reporting reference: IAS 2. These original learning examples apply the displayed formula; the reference does not certify or endorse this calculator.
Look up an accounting term · Practise with accounting questions
Formula and worked example checked 4 November 2026. Calculations run in your browser without sending the entered figures to Accounting Share. Report a calculation issue with the tool name, example inputs and expected result; avoid sharing confidential records.
