Excess and Obsolete (E&O) Inventory Reserve Calculator
An E&O reserve is the provision a company books for inventory it does not expect to sell or use at full cost. Most manufacturers use an age-based matrix because it is simple to audit. This calculator applies one and shows what a change in policy does to the balance sheet and P&L.
Your numbers
Cost value of stock with usage inside 6 months.
Used to express the reserve as a share of sales.
Your results
Reserve percentages are a policy and accounting judgement. Confirm the method with your auditors and applicable GAAP or IFRS requirements.
Reserve vs reserve % on stock over 24 months
Sweeps Reserve % for over 24 months from 0 to 100, holding your other inputs fixed.
Aged inventory list straight from the ERP
Optional: see how last-usage aging could be produced on demand over your ERP data.
Optional. The tool and every export work without this. No spam.
How to use the calculator
Run an inventory aging by last movement or last usage date, and group the cost value into the four buckets. Enter your policy percentages. The default matrix is illustrative, not a recommendation. The chart sweeps the percentage on the oldest bucket, which is usually where the debate with auditors happens.
- Age by last demand or last issue, not by receipt date
- Exclude stock with firm future demand or contracts
- Keep service parts on a separate policy if needed
The method
Reserve = sum over buckets of bucket value x reserve percentage. Net inventory = total - reserve. The increase in reserve from one period to the next is the charge to cost of goods sold. Some companies add a coverage test, comparing on-hand to forecast demand over the next 12 months and reserving any excess; this tool covers the age-matrix method only.
Reading the result
Compare the reserve to revenue and to the prior quarter. A rising share means the aged buckets are growing faster than sales. Before accepting the charge, review the largest items in the oldest buckets for possible returns, rework, or sale to a broker. Salvage value can reduce a 100 percent reserve to a lower figure if supported.
Common mistakes and ERP notes
The usual errors are aging by receipt date, double reserving items already written down to standard, and ignoring negative on-hand or inactive bins. In ERPs, the aging report usually needs a last-transaction field per item and warehouse. Check that a transfer between locations is not resetting the age.
- Reconcile bucket totals to the inventory ledger
- Document every override with approval
- Review the matrix at least annually
Frequently Asked Questions
What reserve percentage should I use?
It depends on your industry and product life. Common matrices run from 0 percent for recent stock to 100 percent for stock with no usage in 24 months or more. Set the policy with your auditors and base it on actual historical write-offs.
Is an E&O reserve tax deductible?
Not usually until the item is physically scrapped or sold below cost, in many jurisdictions. Rules differ, so confirm with your tax adviser. The book reserve and tax treatment often differ.
How is the reserve different from a write-off?
A reserve is a contra-asset estimate that reduces inventory value on the balance sheet while the items remain on hand. A write-off removes the cost of the specific item when it is scrapped or disposed of, usually against the reserve.
Should I age by receipt date?
Generally no. Receipt date penalises slow but steady items. Last usage or last demand date better reflects the risk that stock will never be consumed.
If building the aging takes days of exports, we can show how a read-only ERP agent could list the oldest items with last-usage evidence for your review.
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