Inventory aging analysis shows how long stock has remained without meaningful movement and how much working capital is tied up in slow-moving, excess or potentially obsolete inventory. It complements FSN analysis: FSN classifies movement frequency, while aging highlights how long specific stock has been sitting and where value is at risk.
Why Inventory Aging Matters
- Identifies cash tied up in slow-moving and excess stock.
- Highlights potential obsolescence before write-offs become unavoidable.
- Supports purchasing freezes, return-to-supplier actions and inventory reduction.
- Helps distinguish intentional critical spares from genuinely inactive stock.
- Improves working-capital, warehouse-space and replenishment decisions.
Common Aging Buckets
| Age | Typical Interpretation | Possible Action |
|---|---|---|
| 0–30 days | Recent / active inventory | Normal replenishment control |
| 31–90 days | Monitor movement | Review demand and reorder settings |
| 91–180 days | Slow moving | Reduce replenishment and investigate demand |
| 181–365 days | High aging exposure | Freeze purchases, redeploy, return or discount |
| 365+ days | Potential obsolescence | Formal review for reuse, disposal, return or write-down |
These ranges are planning examples, not universal rules. Shelf life, critical-spare policy, project stock, minimum order quantities and industry requirements can justify different thresholds.
Core Inventory Aging KPIs
Stock Value = On-Hand Quantity × Unit Cost
Age (Days) = Analysis Date − Last Movement Date
Months Cover = On-Hand Quantity ÷ (Annual Demand ÷ 12)
Excess Quantity = MAX(0, On-Hand Quantity − Target Months Cover × Monthly Demand)
Excess Value = Excess Quantity × Unit Cost
Aging Is Not the Same as Excess
An item can be old without being excess, and excess stock can still be recent. A critical spare may have no movement for two years but still be required for business continuity. Conversely, a new purchase can immediately become excess if demand has fallen or the order quantity was too large. Good control therefore combines age, demand, months cover, value and criticality.
How to Classify Slow-Moving and Obsolete Risk
A practical approach is to combine age and stock cover rather than relying on one measure. For example:
- Low: recent movement and stock cover within policy.
- Medium: movement slowing or cover materially above target.
- High: aged stock, long cover or weak demand.
- Obsolete Risk: very old stock with little or no expected consumption, subject to criticality review.
What to Do with Slow-Moving Inventory
- Validate the data. Confirm item codes, last movement dates, stock balances and demand history.
- Stop adding to the problem. Freeze or reduce replenishment where justified.
- Check business criticality. Separate strategic spares, insurance stock and regulatory stock from genuine excess.
- Redeploy internally. Move stock to locations or projects that can consume it.
- Negotiate supplier returns. Especially for standard items, unopened goods or recently purchased excess.
- Use substitution or alternate demand. Identify approved equivalent uses.
- Discount, liquidate or dispose. When recovery value is better than continued storage and obsolescence.
- Fix the root cause. Review forecast bias, MOQ, safety stock, lead time, master data and ordering controls.
Inventory Aging Dashboard
A useful dashboard should show both quantity and value. High-value aging exposure deserves more attention than a large quantity of low-value consumables. Recommended views include:
- Total stock value and total excess value.
- Excess value as a percentage of inventory.
- Stock value by aging bucket.
- High-risk and obsolete-risk exposure.
- Items over 180 and 365 days.
- Action plan with owner, target date and estimated recovery.
Common Inventory Aging Mistakes
- Using receipt date when last meaningful consumption or movement is more relevant.
- Calling all old stock obsolete without checking criticality.
- Measuring quantity but ignoring value.
- Ignoring excess created by excessive months cover.
- Continuing automatic replenishment while slow stock accumulates.
- Creating an aging report without assigning actions and owners.
- Failing to review underlying causes such as MOQ, forecast error or superseded items.
Download the Practical Workbook
Use the SCMANA Inventory Aging & Slow-Moving Stock Dashboard to calculate stock value, days since last movement, aging buckets, months cover, excess quantity/value and risk flags. The workbook also includes a summary dashboard and editable actions/status fields.
Download the Inventory Aging & Slow-Moving Stock Dashboard (Excel)
