In plain English
The income statement is one long subtraction. Start with revenue at the top. Take off what the goods cost to make — that leaves gross profit. Take off the cost of running the place (salaries, rent, marketing) — that leaves operating profit. Take off interest and tax — that leaves net income, the bottom line.
The advanced view
The ladder separates three different questions: gross margin tests pricing power against direct cost, operating margin tests the efficiency of the whole operating base, and net margin folds in financing and tax policy. Only the first two are comparable across companies with different capital structures, which is why EBIT and EBITDA dominate cross-company work.
A margin is just a line of the income statement divided by revenue. Gross margin says how much of each krona survives the direct cost of the product. Operating margin says how much survives running the business. Net margin says how much reaches the owners. Three numbers, three different diagnoses.
An expense is not the same as a payment. Depreciation is an expense with no payment attached this year — the money left when the machine was bought. Paying down a loan is a payment with no expense attached — only the interest is an expense. Keeping those apart is most of what separates a confident reader from a confused one.
The ladder and the margins
Revenue − COGS = Gross profit Gross profit − Operating expenses = Operating profit (EBIT) EBIT − Interest − Tax = Net income Margin = Profit line / Revenue
Essential vocabulary
- COGS
- Cost of goods sold — the direct cost of what was sold: materials, factory labour.
- Operating expenses
- The cost of running the business rather than making the product: salaries, rent, marketing, admin.
- EBIT
- Earnings before interest and tax. Operating profit — what the business earns before financing decisions.
- EBITDA
- EBIT with depreciation and amortisation added back. A rough proxy for operating cash, but it ignores the cost of replacing assets.
- Net income
- The bottom line after everything, including interest and tax. What belongs to shareholders.
Common pitfalls
- ×Quoting 'margin' without saying which one. Gross, operating and net can be wildly different.
- ×Treating EBITDA as cash. A company with heavy capex burns cash while reporting healthy EBITDA.
- ×Comparing net margins across companies with different debt loads and calling it an operating comparison.
Why it works
Each rung of the ladder removes one category of cost, so the drop between rungs isolates that category's effect. When profit falls, walking the ladder tells you within seconds whether the problem is pricing, overhead, or financing — no model required.
How it is used — diagnose a margin in four lines
Step 1 of 5
- 1Revenue 500, COGS 300 → gross profit = 200, gross margin = 200/500 =
Deeper
Deeper: margin bridges and the quality of earnings
A margin never moves for one reason. Decompose any change into price, volume, mix and cost, and quote each as a contribution in currency, not just a percentage. That is the waterfall an interviewer expects: 'EBIT fell 12; input cost −9, volume −4, price +6, mix −2, overhead −3'.
Quality of earnings asks whether the profit is repeatable and cash-backed. Red flags: profit growing faster than operating cash flow for several years, capitalised costs that peers expense, revenue recognised early, and a lengthening list of 'adjusted' items.
Must know cold
- ✓Gross margin = (revenue − COGS) ÷ revenue. EBIT margin = EBIT ÷ revenue.
- ✓EBITDA = EBIT + depreciation + amortisation. It is not cash flow.
- ✓Net income = (EBIT − interest) × (1 − tax rate), ignoring other items.
- ✓Revenue change ≈ price change + volume change (for small changes).
Exercises
Try each one on paper before revealing the worked solution.
Exercise 1
Revenue 500, COGS 300, SG&A 80, D&A 30, interest 15, tax 22%. Compute EBITDA, EBIT, net income, gross margin and EBIT margin.
Exercise 2
Price rises 5%, volume falls 3%, unit cost is unchanged at 60% of the old price. What happens to revenue and gross margin?