Breaking Down COGS
Let’s get into the math of calculating Cost of Goods Sold. The first example will deal with calculating COGS across the entire business. Before we do that though, keep in mind that overall COGS has limited value because you really should know the COGS for each product or service line that you are offering. The more detail in which you know the COGS, the better equipped you are to make decisions on profitability. Also, for a startup, you need to build a financial model from the bottom-up meaning that you will be estimating COGS on a product by product or service by service basis. We will start with the simple calculations and then drive down to the product line basis.
The Basic COGS Formula
For many existing product-based businesses, accountants use this formula to calculate the Cost of Goods Sold (COGS):
Beginning Inventory + Purchases + Direct Labour – Ending Inventory = COGS
This expanded formula matters because in most businesses, labour directly tied to making or delivering your product/service is a major cost.
- Beginning Inventory – Materials or goods you already had at the start of the period.
- Purchases – Any new materials or supplies bought during the period.
- Direct Labour – Wages paid to staff directly involved in production or service delivery.
- Ending Inventory – Materials or goods still on hand at the end of the period.
The result is your COGS: the true cost of turning raw inputs (materials + labour) into sales.
Examples for Product-Based Businesses
Example: A Coffee Shop
- Beginning Inventory (beans, milk, cups): $5,000
- Purchases during the month: $20,000
- Direct Labour (barista wages): $8,000
- Ending Inventory: $7,000
- COGS = $5,000 + $20,000 + $8,000 – $7,000 = $26,000
The $26,000 figure reflects both the ingredients and the labour needed to serve customers.
Example: Furniture Maker
- Beginning Inventory (wood, hardware, varnish): $10,000
- Purchases: $12,000
- Direct Labour (carpenter wages): $15,000
- Ending Inventory: $9,000
- COGS = $10,000 + $12,000 + $15,000 – $9,000 = $28,000
Examples for Service-Based Businesses
Service businesses don’t usually carry inventory, but labour is often the biggest part of COGS.
Example: Consulting Firm
- Subcontractor payments: $8,000
- Software subscriptions used for client delivery: $2,000
- Direct Labour (consultant wages): $15,000
- COGS = $25,000
Example: Landscaping Business
- Materials (soil, plants, mulch): $3,500
- Equipment rental: $1,200
- Direct Labour (crew wages): $7,000
- COGS = $11,700
Common Mistakes in COGS Calculations
- Leaving out direct labour. Many entrepreneurs mistakenly treat all wages as operating expenses, but it’s important to separate direct labour from indirect labour when calculating COGS. Direct labour includes employees or contractors whose work is directly tied to producing or delivering the product or service (e.g., baristas making drinks, carpenters building furniture, landscapers installing sod, or consultants delivering billable hours) and therefore belongs in COGS. Indirect labour covers roles that support the business but cannot be tied to a specific sale (e.g., managers, bookkeepers, or sales staff) and should be classified as operating expenses. Misclassifying labour can make gross profit appear higher than it truly is, leading to underpricing and poor financial decisions.
- Forgetting the “small stuff.” Packaging, consumables, and shipping costs are often ignored.
- Misclassifying management salaries. Supervisors, salespeople, and admin staff do not go into COGS — only hands-on labour counts.
- Not tracking subcontractors or temporary staff. If they’re part of fulfilling an order, their cost belongs in COGS.
- Inventory blind spots. Not properly counting beginning and ending inventory can inflate or deflate COGS, leading to misleading margins.
Developing a Bottom-Up Estimate of COGS
A bottom-up estimate starts by identifying all the individual cost components required to produce and deliver one unit of your product or service, then summing them up. This approach forces you to think about every input — materials, direct labour, and production-related overhead — so you don’t underestimate your true costs.
Steps to Build a Bottom-Up Estimate
- List all materials or inputs needed for one unit of the product/service.
- Add direct labour costs for the time staff spend producing or delivering one unit.
- Include production-related overhead (e.g., packaging, utilities for production space, equipment rental).
- Sum these costs to calculate the per-unit COGS.
- Multiply by sales volume to forecast total COGS for the product line.
Example 1: Product-Based Business (Coffee Shop – Latte)
- Materials per latte:
- Coffee beans: $0.50
- Milk: $0.30
- Cup + lid: $0.20
- Syrup (average): $0.15
- Direct Labour per latte:
- Barista time: 2 minutes at $15/hour = $0.50
- Overhead allocation per latte:
- Portion of utilities + cleaning supplies = $0.10
Total COGS per latte = $1.75
If the shop sells 1,000 lattes in a month, Total COGS = $1.75 × 1,000 = $1,750.
Example 2: Service-Based Business (Landscaping – Lawn Mowing Job)
- Materials per job:
- Gasoline for mower: $5.00
- Equipment wear/maintenance allocation: $2.00
- Direct Labour per job:
- Crew member: 1 hour at $20/hour = $20.00
- Overhead allocation per job:
- Portion of truck fuel/insurance = $3.00
Total COGS per mowing job = $30.00
If the company books 50 jobs in a month, Total COGS = $30 × 50 = $1,500.
✅ Takeaway:
A bottom-up approach ensures you capture the true cost per unit of your product or service. This level of detail not only prevents underpricing but also helps identify where efficiencies or cost savings can be made. For a new business with no operational history, this is the only way to determine COGS. For an existing business, these numbers should be reviewed regularly based upon actual operation to allow for regular assessments of the gross profit per product or service.
Using COGS to Drive Decisions
Setting Prices with COGS in Mind
COGS is the foundation of every pricing decision. If you don’t know your true cost per unit, you risk setting a price that doesn’t cover your expenses or leaves little room for profit. By calculating COGS first, you can set a price that ensures each sale contributes to your gross profit. For example, if a latte costs $1.75 in COGS and you sell it for $4.00, your gross profit per unit is $2.25. Without this awareness, you may celebrate high sales while unknowingly losing money on every cup.
Understanding Gross Margin and Markup
Many entrepreneurs confuse margin and markup, but they measure different things.
- Markup is how much more you charge compared to your cost. If it costs you $10 to make a product and you sell it for $15, your markup is 50%.
- Gross Margin shows what percentage of the selling price you keep after covering COGS. Using the same example, your gross profit is $5, and your gross margin is $5 ÷ $15 = 33%.
Knowing the difference helps you make smarter decisions about pricing, discounts, and promotions. Markup ensures you cover costs, while gross margin tells you whether your business model is sustainable.
Monitoring Profitability by Product/Service Line
Not all products or services contribute equally to your bottom line. By tracking COGS and gross profit for each line, you can see which offerings are profitable and which are dragging you down. A clothing retailer, for example, may discover that t-shirts have a 20% margin while jackets deliver 50%. Even if t-shirts sell in higher volume, jackets may be the real profit drivers. This insight allows entrepreneurs to adjust product mix, marketing focus, and even staffing to maximize overall profitability.
Using COGS to Improve Cash Flow
COGS also plays a direct role in cash flow management. High COGS can tie up cash in inventory or excessive labour, leaving little flexibility to pay suppliers, employees, or reinvest in growth. Regularly reviewing your COGS helps you spot waste (like over-ordering, high spoilage, or inefficient labour) and take corrective action. For example, a landscaping company that notices rising fuel costs in its COGS can respond by optimizing routes or negotiating better fuel rates. Each small adjustment improves cash flow and strengthens the business’s financial position.
✅ Takeaway:
COGS isn’t just an accounting number—it’s a decision-making tool. It guides pricing, shapes strategy, reveals product-level profitability, and helps keep cash flowing.
Risks of Poor COGS Management
Pricing Below Cost Without Realizing It
One of the biggest risks of poor COGS management is unknowingly setting prices too low. If you don’t fully account for all materials, direct labour, and other production-related costs, your selling price might look profitable but is actually below cost. This creates the illusion of strong sales while eroding your margins with every transaction. For example, a bakery that forgets to include packaging and staff time in its COGS may believe it makes $2 profit per pastry, when in reality it’s breaking even—or worse, losing money.
Over- or Under-Estimating Inventory
Accurate inventory counts are critical for calculating COGS. Overestimating ending inventory lowers your reported COGS and inflates gross profit, giving a false sense of financial health. Underestimating inventory does the opposite—it makes your COGS appear higher and can make the business look less profitable than it actually is. Both mistakes create confusion in pricing, purchasing, and cash flow management. Imagine a retailer ordering more stock than needed because they think inventory is low—this ties up cash and increases the risk of waste or unsold goods.
Cash Flow Crunches
Poor COGS management often leads to unexpected cash flow problems. If costs aren’t tracked accurately, you may think your business is generating healthy profits when, in fact, it is consuming more cash than it brings in. This disconnect can cause shortfalls when it comes time to pay suppliers, staff, or loan obligations. For example, a service business that doesn’t account for subcontractor fees in its COGS may appear profitable on paper, but struggle to cover bills each month. Ultimately, ignoring COGS can leave you scrambling for cash just to keep the doors open.
Tax and Compliance Issues
COGS is not just a management tool; it’s also a key part of tax reporting. Misclassifying costs (for example, treating direct labour as operating expenses) can distort your financial statements and lead to errors in taxable income. Overstating expenses can trigger audits and penalties, while understating them may cause you to pay more tax than necessary. Accurate COGS ensures compliance with accounting standards and keeps you out of trouble with tax authorities.
✅ Takeaway:
Failing to manage COGS properly exposes entrepreneurs to serious risks: selling at a loss, making poor purchasing decisions, facing tax complications, and running into cash shortages. By treating COGS as a central metric rather than an afterthought, you can avoid these pitfalls and build a stronger financial foundation.