Writing Down Obsolete and Slow-Moving Inventory: Lower of Cost or Net Realizable Value Explained

A parts distributor counts 400 widgets at $50 each — $20,000 on the balance sheet. In the warehouse, 120 of them have sat for 18 months, superseded by a new model customers actually want. The owner can sell them for $20 if they pay $5 to ship, but the books still say $50. At year-end the bank reviews the balance sheet, the auditor asks for the inventory aging, and suddenly that $20,000 is a covenant problem and a tax question the owner can't answer without a frantic spreadsheet.

That gap — between what you paid and what you can actually realize — is what the lower of cost or net realizable value (LCNRV) rule exists to close. You already know the instinct: don't carry inventory at more than it's worth. The accounting just gives that instinct a definition, a test, and a journal entry.

The Rule in One Sentence​

Under U.S. GAAP (ASC 330), inventory is reported at the lower of its cost or its net realizable value (NRV) — the amount you can actually collect on sale in the ordinary course of business.

If cost is $50 and NRV is $15, you carry it at $15 and recognize the $35 loss now. If cost is lower than NRV, you do nothing — you don't write inventory up above cost.

This is conservatism with a purpose: recognize losses when they become probable, not when the dusty pallet finally goes to the landfill.

What Counts as "Cost" — and What Counts as NRV​

Cost​

For most small businesses, cost is straightforward:

• Purchased goods: Invoice cost plus freight-in, duties, and other costs to get the item to its present location and condition. Not freight-out, not selling commissions.
• Manufactured goods: Direct materials + direct labor + allocated overhead (the full absorption cost that lives in work-in-process and finished goods).
• Cost flow assumption matters at write-down: FIFO, weighted-average, and specific identification each produce a different "cost" per unit. You apply LCNRV after the cost flow, unit by unit or by homogeneous group — not to the pooled total to hide an obsolete SKU behind a fast-moving one.

Net Realizable Value​

NRV is not "market price." It is expected selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The classic formula:

NRV = Estimated selling price
      − Estimated costs to complete (for WIP)
      − Estimated costs to sell (commissions, marketplace fees, packaging for sale)
      − Estimated transportation / disposal costs

For finished goods: selling price minus selling and transportation.

For work-in-process: expected selling price of the finished good minus remaining completion costs minus selling and transportation.

For raw materials held for production: generally NRV is derived from the finished good it will become — write down raw if the finished good's NRV has fallen below its total cost to produce.

Example — finished widgets:

• Cost on books: $50
• You can sell the obsolete model for $22 on clearance
• Marketplace fee 10% = $2.20, freight to customer $4.80, no completion cost
• NRV = $22 − $2.20 − $4.80 = $15
• Write-down per unit = $50 − $15 = $35

Example — work-in-process circuit board:

• Accumulated cost so far: $80
• You have $30 of components and labor left to finish it
• Expected selling price as finished unit: $95, with $8 to ship and sell
• NRV for this WIP = $95 − $30 − $8 = $57
• Since $57 < $80, write down $23 now — you already know you cannot recover the rest through sale.

When to Test — Triggers That Say "Run the NRV Check"​

You don't need to NRV-test every SKU every month. You do need to test when facts suggest NRV has dropped. Build these triggers into your month-end:

• Aging. Anything with no movement in 6–12 months (or 2× your normal turn) gets flagged. The classic slow-moving report — quantity on hand ÷ average monthly usage — surfaces the tail.
• Supersession. New model, new spec, new regulation renders the old SKU unsellable at normal price. The moment engineering calls it superseded, the old SKU is NRV-candidate.
• Damage, spoilage, or obsolescence. Water damage, shelf-life expiry, tech that missed the cycle, fashion that missed the season — if you wouldn't buy it at cost, neither will a customer.
• Price pressure. You cut list price 30% to clear stock, or a competitor's new product forces a permanent price reset. NRV moved; cost didn't.
• Below-cost contracts. A firm sales order at a price below cost is direct evidence of NRV < cost for that quantity.
• Post-balance-sheet sales. You sold units after year-end at a clearance price — that sale is evidence of NRV at year-end, even though it happened later.

Do the test at the balance sheet date, not when you get around to it. An auditor will ask what you knew at that date, including post-year-end sales that illuminate it.

How to Do the Write-Down — Mechanics That Survive an Audit​

1. Group at the right level​

ASC 330 applies at the item level or by groups of similar items — not by blending a dead SKU's loss into a hot SKU's margin. Grouping washing-machine hoses with fashion handbags to avoid a write-down will not survive review.

For entrepreneurshipers and distributors with thousands of SKUs, grouping by homogeneous category (e.g., "2024-model chargers, 65W") is practical and defensible. Document the grouping logic and apply it consistently.

2. Choose one of two entry styles — and stick with it​

Direct method (most common for small businesses):

Debit  Cost of Goods Sold (or "Loss on write-down to NRV")   $X
  Credit  Inventory                                           $X

Allowance method (better for tracking and potential disclosure):

Debit  Loss on write-down to NRV                               $X
  Credit  Allowance to reduce inventory to NRV                  $X

On the balance sheet, inventory is shown net of the allowance (Inventory at cost $20,000 less allowance $4,200 = $15,800). The allowance lets you show what was written down without losing the cost history — useful when the same SKU bounces between periods.

Either method hits gross profit; neither touches revenue. Don't bury the write-down in "other expenses" where margin analysis loses it. Many businesses use a separate "inventory write-down" line within COGS for visibility.

3. Don't reverse under GAAP (but understand IFRS)​

U.S. GAAP: no reversal. Once you write inventory down to NRV, that new amount becomes the cost basis. If the market recovers next quarter, you don't write it back up — you recognize the gain only when you actually sell at the higher price.

IFRS (IAS 2): reversal is required when the reason for the write-down no longer exists, capped at the original cost. If you report under both or your buyer does, tracking the original cost alongside the allowance matters.

4. Tie it to physical reality​

A write-down without a disposition plan is half the job. For each written-down lot, decide: clearance price, bundle, return to supplier, donate, scrap — and record the actual outcome against the estimate. The variance between estimated NRV and actual proceeds is your feedback loop for next quarter's estimate.

A Month-End Workflow You Can Run This Week​

If you've never done a systematic NRV review, here is a minimal loop that fits a small operation:

Day 1–2: Export and age. Pull inventory by SKU: quantity, unit cost, last movement date, quantity sold trailing 6 months, current list price, and marketplace/channel fees. Compute months of supply (on hand ÷ avg monthly sales). Flag >6 months and zero-movement SKUs.

Day 3: Price-check the flag list. For each flagged SKU, get a real selling reference: your current clearance price, a firm quote, or a recent sale of the same or substantially similar item. Subtract completion/selling/transport to get NRV. Document the source (screenshot, quote email, sales invoice) — "manager estimate" alone is weak in an audit.

Day 4: Compute and post. For each SKU where cost > NRV, calculate write-down (quantity × (cost − NRV)). Post via the chosen method. Keep a simple schedule:

SKU | Qty | Unit cost | Est. sell price | Costs to sell | NRV | Write-down | Evidence | Disposition

Month-end: Disclose and review. If write-downs are material, disclose the amount and the fact that inventory is stated at LCNRV in your notes. Review actual clearance proceeds vs NRV estimates — persistent over-optimism in NRV is the most common audit finding.

Five Mistakes That Quietly Overstate Inventory​

1. Averaging away the problem. Offsetting an obsolete SKU's loss against a high-margin SKU's "headroom" at the category total. Test at the item or homogeneous-group level.

2. Using list price as NRV. List is not realizable if you only sell at 40% off. NRV must reflect the price you actually expect in the ordinary course, net of real selling costs.

3. Forgetting costs to sell. A $22 clearance sale with $7 in fees and freight is a $15 NRV, not $22. Omitting marketplace fees is a classic overstatement.

4. Ignoring WIP and raw materials. Writing down only finished goods while WIP and raw for the same dead product sit at full cost. If the finished good is impaired, the inputs likely are too.

5. Treating the write-down as a one-time event. Slow-moving inventory is a flow, not an accident. Without a monthly aging review, the same SKUs drift for a year and the write-down becomes a year-end surprise that breaks a covenant or a tax estimate.

The Inventory–Tax Connection (Without Overpromising)​

For tax, inventory write-downs to NRV generally align with book for most small businesses using accrual methods, but timing and method-election nuances exist (e.g., the treatment of reserves vs direct write-downs, and the uniform capitalization rules of §263A for producers and resellers above the $30M gross-receipts threshold). A book write-down reduces taxable income when it reduces COGS; an allowance that is merely an estimate may need to be a direct reduction to be deductible. Confirm the posting method and §263A interaction with your CPA before relying on the book number for an estimated payment — the economics are the same, the line on the return may differ.

The Bookkeeping Connection​

Inventory is where accounting meets the warehouse. The discipline that makes LCNRV painless is the same discipline that makes your ledger trustworthy: every SKU has a cost, a last-movement date, and a realizable value you can point to, version-controlled alongside the entry that wrote it down. When costing, NRV, and disposition live in the same ledger — not in three spreadsheets — the auditor's question ("why this NRV?") has an answer that is a commit, not a memory.

Plain-text accounting earns its keep here: a write-down that is a single journal entry away from the aging report that justified it, with the evidence link in the commit message, beats a year-end adjustment no one can explain in February.

Simplify Your Financial Management​

Writing down obsolete inventory is not pessimism — it is accuracy. Carrying stock at what you paid when you can only realize a fraction overstates assets, overstates profit, and hides the purchasing or product decision that needs attention. Beancount.io gives you plain-text, version-controlled accounting where inventory cost, NRV, and the write-down are explicit and auditable — one ledger, one history, no hidden reserves. Track every SKU, every adjustment, and every sale from cost to cash in a file you own. Get started for free and keep your balance sheet as honest as your warehouse count.