Definition
Cost of Goods Sold (COGS) represents the direct costs attributable to producing or delivering the goods and services a business sells. It includes materials, direct labor, and any costs directly tied to production.
COGS by Business Type
- E-commerce/Retail: Product costs, shipping, packaging, payment processing fees.
- SaaS: Hosting infrastructure, third-party API costs, customer onboarding labor.
- Services: Direct labor (employee or contractor time spent on client deliverables).
- Construction: Materials, subcontractor costs, equipment rental for specific jobs.
How to Calculate It
COGS = Beginning Inventory + Purchases During the Period − Ending Inventory
For service businesses without inventory, COGS is typically the direct labor and third-party costs allocated to client work. For SaaS, it's hosting, infrastructure, and any per-customer costs. The key distinction: if a cost exists regardless of whether you make a sale, it's not COGS — it's an operating expense.
Why It Matters
COGS determines your gross margin — the most fundamental indicator of whether your business model works. If COGS is too high relative to revenue, no amount of growth will make the business profitable — you're losing money on every sale before you even pay for sales, marketing, or overhead. If COGS is increasing as a percentage of revenue, your unit economics are deteriorating.
Example
An e-commerce brand does $500K in revenue for the quarter. Beginning inventory was $120K, they purchased $280K in new inventory, and ending inventory is $100K. COGS = $120K + $280K − $100K = $300K. That gives them a gross margin of 40%. If a supplier raises prices 10% next quarter and they don't adjust retail pricing, COGS jumps to $330K and gross margin drops to 34% — a $30K hit to gross profit on the same revenue.
What to Watch For
- Misclassifying operating expenses as COGS. Rent, marketing, and admin salaries are not COGS. Including them inflates the number and distorts your gross margin.
- Ignoring COGS in service businesses. Many agencies and consultancies treat all costs as overhead. But the hours your team spends on client deliverables are direct costs — and tracking them as COGS gives you a real picture of project-level profitability.
- Not tracking COGS as a percentage of revenue over time. The absolute number matters less than the trend. A 2-point increase in COGS-to-revenue ratio over six months signals a problem that compounds fast.
How CentSight Helps
CentSight tracks COGS from your QuickBooks data and monitors it as a percentage of revenue over time. It flags COGS increases early — a vendor raising material costs by 5%, hosting costs creeping up as usage grows, or freelancer rates drifting above budget.