COGS vs. Overhead: Sort Your Costs or Misread Everything
COGS vs. Overhead: Sort Your Costs or Misread Everything
Every cost in your business belongs to one of two families: costs of delivering the thing you sell, and costs of existing as a company. Mix them up and every downstream number — gross margin, pricing, break-even, what a new sale is worth — comes out wrong. This is unglamorous, and it is load-bearing.
The sorting test
Cost of goods sold (COGS) — sometimes "cost of sales" or "direct costs" in service businesses — is any cost that scales with delivery. The test: if you sold zero this month, would the cost be zero?
- Materials and parts that go into the product
- Labor paid to deliver the specific job (the crew's hours on the install, the contractor who built the client's site)
- Payment processing fees on sales
- Shipping the product to the customer
- Software seats you buy per client to serve them
Overhead (operating expenses) is what you pay to exist, sell zero or sell a hundred:
- Rent, utilities, insurance
- Your bookkeeper, your general software stack, your phone
- Marketing and ads (you pay whether or not they convert)
- Salaries not tied to a specific delivery — including, usually, you
Gray areas exist. The owner who both runs the company and works the jobs is part-COGS, part-overhead — split by hours if the split is material. Ads are overhead on the P&L even though they "drive sales," because they don't scale with delivery (their per-customer economics live in CAC — that's a different lesson, a different tool). Don't agonize: pick a rule, write it down, apply it the same way every month. Consistency beats precision here, because what you're really building is comparability month over month.
Why the sort changes decisions
Pricing. Price must clear COGS with enough left over (gross profit) to cover a fair share of overhead and profit. Owners who lump everything together price by vibes — usually too low, because the true cost of delivery is understated. The pricing lessons in this pillar all assume this sort is done.
Reading a good or bad month. Revenue up, profit flat — why? If COGS grew in proportion, delivery costs are stable and overhead ate the gain (find which line). If COGS grew faster than revenue, each sale got more expensive to deliver — supplier prices, rework, discounting. Two completely different fixes, distinguishable only if the sort is clean.
What a new sale is worth. One more sale costs you its COGS, not its "share of everything." Overhead doesn't rise when you sell one more unit. That's the idea contribution margin builds on, and it's why a clean sort tells you how much a marginal customer is truly worth — which drives what you can spend to get one.
Scale math. COGS-heavy businesses (agencies, trades, manufacturing) grow revenue and costs together; the win is margin discipline per job. Overhead-heavy businesses (software, content, products with cheap delivery) bleed until revenue covers the fixed base, then compound. Knowing which animal you are tells you what growth will feel like.
Numbered: clean up your sort this week
- Export your P&L category list (chart of accounts — the Operations pillar has a full lesson on it).
- Walk every expense category through the zero-sales test. Would this cost hit zero if we sold nothing? COGS. Would it march on? Overhead.
- Restructure the P&L so COGS sits above the gross profit line and overhead below it. Every mainstream bookkeeping tool supports this; it's a one-time setup.
- Split any category that's genuinely both. "Labor" usually becomes "direct labor" (COGS) and "admin payroll" (overhead). This one split fixes most service-business P&Ls.
- Write the rules down — three lines in a note: what counts as direct, how you split your own time, where processing fees go. Future-you (and any bookkeeper you hire) applies the same rules, and your months stay comparable.
- Re-run last month with the clean sort and look at your real gross margin, possibly for the first time. That number feeds the next lesson.
For tax purposes, COGS has its own formal computation (the IRS's Publication 334 chapter on it covers inventory-based businesses). Your management sort and the tax computation are cousins, not twins — keep the management sort decision-useful and let your CPA handle the return.