Your COGS Is Probably Wrong: Hidden Costs Killing Your Margin

The COGS Calculation Most SMBs Are Getting Wrong#

Ask most SMB owners what their cost of goods sold is and they'll give you a number. Ask them what's in that number, and it almost always turns out to be just the supplier invoice. The true cost of goods sold includes every cost incurred to get a product to a saleable state in your location. For a retailer, that means: supplier invoice + inbound freight + import duty + customs brokerage fees + warehousing + picking and packing + packaging materials + quality control labour + write-offs for damaged or rejected units. For a manufacturer: raw materials + inbound freight + direct labour + machine time allocation + tooling depreciation + quality control + outbound freight. Miss any of these layers and your COGS is understated — meaning your margin is overstated, and your prices may be set too low.

How Much Are You Understating COGS? Industry Estimates#

In a 2023 Xero analysis of 2,400 UK SMBs, businesses that tracked COGS using only supplier invoices understated true COGS by an average of 18% compared to businesses using full landed cost tracking. In practical terms: a business that thinks its gross margin is 48% is actually running at around 39% if COGS is 18% understated. That 9-point gap means £27,000 less profit per year on a £300,000 revenue business — profit you thought you were making but never actually was. The business feels healthy until the cash flow or tax bill tells a different story.

The Five Costs Most Commonly Missing from COGS#

Cost 1 — Inbound freight: often coded as an overhead expense rather than directly to products. Should be allocated per unit based on weight or volume. Cost 2 — Import duty: particularly relevant post-Brexit for UK businesses importing from EU or Asia. Cost 3 — Packaging: hang tags, boxes, void fill, tape — often £0.15-£0.60 per unit but frequently coded to stationery or supplies. Cost 4 — Wastage and shrinkage: 1-4% of stock is typically damaged, stolen, or expired — a real cost that should be in COGS. Cost 5 — Direct labour: for businesses that pick, pack, or customise products in-house, the labour hours spent are direct production costs, not overhead.

How to Fix Your COGS Calculation in Xero#

In Xero, accurate COGS tracking requires: (1) using inventory items rather than expense accounts for all product purchases — this enables proper COGS calculation at point of sale, (2) coding inbound freight to specific product categories rather than a general freight account, (3) recording duty and brokerage fees against the relevant product import batches, (4) creating a wastage/shrinkage provision account coded as COGS, not overhead. Once these are set up correctly, Xero calculates COGS on a per-sale basis — and AskBiz pulls those figures to show you real gross margin per SKU at the moment of sale.

AskBiz: Catching the COGS You're Missing#

AskBiz integrates with Xero to pull live COGS data per product line. It compares your Xero-reported COGS against the supplier invoice cost you're holding in your inventory records — and flags any discrepancy above a threshold. If your inventory shows an average cost of £12.50 for a product but your Xero COGS (including freight and duty) is running at £15.80, AskBiz surfaces that gap. You can then either update your inventory cost records or investigate what's being coded incorrectly. This reconciliation catches the systematic undercounting that most SMBs live with unknowingly for years.

Calculating True Margin After COGS Correction#

Once you have accurate COGS, recalculate gross margin on your top 20 SKUs. The exercise is often revealing: products you thought were generating 52% margin may actually be at 38%. Products you considered low-margin staples may actually be your most profitable. One UK gift retailer discovered after correcting COGS that her five highest-margin products were all handmade items with relatively low material costs — but she'd been promoting and featuring her mass-produced lines because she assumed they were more profitable. The COGS correction changed her entire buying and merchandising strategy.

Using Accurate COGS to Set Prices Correctly#

The purpose of accurate COGS is to price from a solid foundation. If your true landed cost per unit is £8.85 (not £6.50), and you want a 50% gross margin, your minimum price is £17.70 (not £13.00). That £4.70 difference is not theoretical — it's the difference between building a sustainable business and slowly eroding your capital. Accurate COGS turns pricing from a guess into a calculation. It's the single most important foundation for any pricing strategy, and it costs nothing to set up correctly in Xero once you understand what belongs there.

• Accurate COGS is the foundation of every pricing and profitability decision.
• Most SMBs undercount it significantly — missing freight, duty, packaging, wastage, and handling costs.
• AskBiz and Xero together capture all of these and show true per-SKU margin automatically.