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FIFO Calculator for Inventory

Use this FIFO inventory calculator to model oldest-first inventory depletion before reviewing margin, stock value, or accounting scenarios.

Planning estimate

Live calculator

FIFO calculator for inventory

FIFO COGS$1,620

120 oldest units plus 60 newer units.

Ending inventory$1,540

140 units remain after FIFO depletion.

Gross margin50.00%

Inventory covers sales

FIFO inventory summary

FIFO consumes older inventory layers first and leaves newer purchase costs in ending inventory. Keep units, cost basis, and period cutoffs consistent.

FIFO measureValue
Available units320
Units fulfilled180
Unfilled units0
Beginning layer consumed120
Purchase layer consumed60
COGS$1,620
Ending inventory value$1,540
Revenue$3,240
Gross profit$1,620
Planning note

FIFO is a cost-flow assumption, not a physical stock guarantee. Validate lot dates, returns, write-downs, freight treatment, and accounting policy before using the output for books or tax filings.

Planning comparison only. Check estimates, omitted costs, timing, and constraints before making an operating decision.

Formula

FIFO inventory formula

FIFO COGS = oldest units sold x oldest unit cost, then next-oldest units x next unit cost; ending inventory = remaining units x their layer costs

FIFO assumes the earliest acquired inventory costs flow to COGS first, leaving newer costs in ending inventory.

How to use

Steps

  1. Enter beginning inventory quantity and unit cost for the oldest stock layer.
  2. Enter the next purchase quantity and unit cost.
  3. Enter units sold or issued from inventory.
  4. Add selling price if you want revenue, gross profit, and gross margin context.
  5. Review COGS, ending inventory, and unfilled units before using the result in a ledger.

Example

Sample calculation

Beginning layer120 units @ $8.00
Purchase layer200 units @ $11.00
Units sold180
FIFO output$1,620 COGS; $1,540 ending inventory

Calculator use

Best for

  • Pricing, runway, cash flow, or work assumptions before an operating decision.
  • Base, conservative, and optimistic cases with visible inputs.

Before relying on it

Check first

  • FIFO assumes the earliest acquired inventory costs flow to COGS first, leaving newer costs in ending inventory.
  • Mixing scenarios, units, or time periods in one comparison.
  • Leaving out material costs, capacity limits, uncertainty, or dependencies.

Details

What to know before using the result

COGS sequenceOldest inventory first

The calculator consumes beginning units before assigning cost from the newer purchase layer.

Ending stockRemaining layer value

When costs rise, FIFO usually leaves newer, higher costs in ending inventory.

Planning boundaryCost-flow estimate

Validate returns, shrinkage, write-downs, freight treatment, and accounting policy before final reporting.

Source notes

References used for this calculator

OpenStax Financial AccountingExplains FIFO as earliest purchased units sold first, with newer costs remaining in ending inventory.

Benchmarks

How to read the result

COGS: Oldest sold units x oldest layer cost.

Consumes each inventory layer in acquisition order until the sale quantity is filled.

Ending inventory: Remaining units x layer cost.

The unsold units keep their original layer costs in the model.

Gross margin: (Revenue - FIFO COGS) / revenue.

Only meaningful when selling price and fulfilled sold units are entered.

Calculator accuracy

Methodology and assumptions

Formula, inputs, limitations and review record
Formula

FIFO COGS = oldest units sold x oldest unit cost, then next-oldest units x next unit cost; ending inventory = remaining units x their layer costs

Inputs used

Beginning units, Beginning unit cost, Purchase units, Purchase unit cost, Units sold, Selling price

Limitations

Business results depend on contracts, accounting treatment, taxes, payment timing, refunds, collections, and operating assumptions.

Review record

Catalog QA baseline on June 6, 2026. This date marks the catalog-wide automated and editorial QA baseline, not a tool-specific expert review.

Cite this page

Toolkit Shelf. FIFO Calculator for Inventory. https://toolkitshelf.com/tools/fifo-calculator-for-inventory

FAQ

Common questions

What does FIFO mean for inventory costing?

FIFO means first-in, first-out. The oldest inventory costs are assigned to cost of goods sold before newer purchase costs.

Does FIFO track the exact physical item sold?

Not necessarily. This calculator models the accounting cost-flow assumption, so validate physical lot tracking separately if that matters.

Why can FIFO change gross margin?

When unit costs change, FIFO decides which cost layers move to COGS. Lower older costs usually raise reported margin compared with newer higher-cost layers.