What gross margin is and why it matters
Gross margin shows how much money you keep from sales after you pay the direct costs to make or buy what you sell. It tells you if product pricing and direct costs are healthy. A good gross margin gives room to pay rent, payroll, marketing, and make a profit.
Key terms (simple)
- Revenue (Sales): Money you get from selling goods or services.
- Cost of Goods Sold (COGS): Direct costs tied to those sales — materials, manufacturing, direct labor, shipping to get goods ready to sell.
- Gross Profit: Revenue minus COGS.
- Gross Margin (%): (Gross Profit ÷ Revenue) × 100.
Step-by-step: Calculate gross margin
- Pick a time period. Use a month, quarter, or year. Be consistent.
- Calculate revenue for that period. Add all sales (use invoice totals or POS totals). Example: $50,000 in sales this month.
- Calculate COGS for the same period. Add only the direct costs tied to those sales: materials, direct labor on the product, shipping in, packaging used to fulfill orders. Exclude rent, admin, and marketing. Example: $30,000 in direct costs.
- Compute gross profit. Revenue − COGS. Example: $50,000 − $30,000 = $20,000.
- Compute gross margin percentage. (Gross Profit ÷ Revenue) × 100. Example: ($20,000 ÷ $50,000) × 100 = 40%.
Two quick examples
Retail example: You sold $25,000 of apparel. You bought that inventory for $12,500 and paid $500 for shipping in. COGS = $13,000. Gross profit = $12,000. Gross margin = 12,000 ÷ 25,000 = 48%.
Service example: A cleaning company invoiced $10,000 in jobs. Direct labor for those jobs was $4,000 and cleaning supplies $500. COGS = $4,500. Gross profit = $5,500. Gross margin = 55%.
Common mistakes to avoid
- Including rent, utilities, admin payroll, or marketing in COGS — those are operating expenses, not COGS.
- Mixing periods — match sales and COGS to the same time frame.
- Using retail price as cost — COGS should be what you paid or direct labor cost, not what you charge customers.
Simple checklist to run now
- Choose period (month/quarter/year)
- Export sales total from POS or accounting
- List direct costs tied to those sales
- Subtract: Revenue − COGS = Gross Profit
- Divide and convert to percent: (Gross Profit ÷ Revenue) × 100
- Record the result and compare to prior periods
Decision rules — what to do with the number
- If gross margin is low (<20%): Increase prices or lower COGS. Quick wins: negotiate supplier prices, reduce waste, switch to higher-margin items.
- If margin is moderate (20–40%): Watch trends. Try small price increases, improve purchasing, or push higher-margin offerings.
- If margin is high (>40%): You have room to cover overhead and invest. Re-check COGS accuracy to confirm.
How often to check
Monthly if you have fast-moving sales. Quarterly if sales are slower. Check after major price or supplier changes.
How to track over time
Create a simple spreadsheet with columns: Period, Revenue, COGS, Gross Profit, Gross Margin %. Compare month to month and flag drops greater than 3–5 percentage points.
When to get help
Ask an accountant if COGS is hard to define (complex inventory, work-in-process, or payroll allocation). For quick checks, the steps here are enough to spot problems and take action.
One-page cheat sheet
- Step 1: Revenue = total sales
- Step 2: COGS = direct costs only
- Step 3: Gross Profit = Revenue − COGS
- Step 4: Gross Margin % = (Gross Profit ÷ Revenue) × 100
- Decision rule: <20% — fix price/cost; 20–40% — improve; >40% — invest/save