Free Obsolete Inventory Calculator
Calculate obsolete inventory percentage from obsolete inventory value and total inventory value.
When to use this calculator
Obsolete inventory percent shows how much stock is no longer salable at full value — slow movers, superseded SKUs, or damaged goods reserved for write-down. Finance and inventory control use it before quarter close and clearance events. Track when engineering changes revisions or when MOQ buys strand leftovers.
Methodology and inputs
Obsolete % = obsolete inventory value ÷ total inventory value × 100. Define obsolete by policy: no sales 12 months, below salvage, or flagged by PLM revision — value at lower of cost or net realizable.
Worked example
Electronics importer carries $2.1M inventory; $318k tagged obsolete (prior-gen accessories, carton damage). Obsolete = 15.1% — above a 10% policy cap triggering a $45k Q3 write-down and bundle promo budget.
How to interpret the result
Rising obsolete percent with healthy turnover elsewhere means assortment governance failed, not overall demand. Sudden drops may mean write-offs hit P&L — verify it is disposal, not reclassification without sale.
Reviewed by ZBI Tools · Practical finance and operations calculators for SMB teams.
Further reading
For a deeper walkthrough of the concepts behind this tool, see our guide: Read the full analysis guide.
Related hub: Browse all calculators · Analyzers & calculators home · About Zen Box Infinity
Practical questions
Is slow-moving obsolete?
Only when policy says so — many firms stage slow then obsolete tiers.
Partial obsolescence?
Use NRV testing on lots — do not wait for full write-off if market price collapsed.
Include WIP?
If WIP cannot be reworked profitably, include per inventory policy.
Formulas
Obsolete Inventory % = Obsolete Value ÷ Total Inventory Value × 100
Example: Obsolete EUR 35,000; total inventory EUR 400,000 → 8.75%.
Source: ZBI Business Control Library — obsolete-inventory-percent.
FAQ
What is obsolete inventory?
Stock with no demand, expired shelf life, or superseded SKU status.
What is a warning sign?
Rising obsolete % while total inventory grows—cash trapped in dead SKUs.