An income statement tells the story of how a company earns money (revenue) and what it spends to run the business (expenses) over a period (a quarter or a year). If you can read it, you can quickly answer: Is the business model working? Are profits improving? What’s driving changes—pricing, volume, costs, debt, or taxes?
Think of it as a “movie” of performance over time, not a “snapshot” like the balance sheet.
Most income statements follow a similar staircase:
Money earned from selling products/services. You’ll often see net sales (after returns/discounts).
COGS is the direct cost to produce/deliver what was sold. Gross profit = Revenue − COGS. This is where you start seeing the economics of the product.
Operating expenses (often SG&A, R&D, marketing) are the costs to run the business beyond producing the product. Operating income reflects profit from core operations before financing and taxes.
Commonly interest expense/income and other gains/losses not central to operations.
What’s left for shareholders after all expenses.
A few common variations: some companies show EBITDA (EBIT plus depreciation/amortization), and some separate one-time or unusual items to help readers see “normalized” performance.
A company’s revenue is flat year over year, but net income drops sharply. Which part of the income statement is the best place to look first to identify where the drop is coming from?
When revenue is flat but net income falls, the change must be happening in the layers below revenue: COGS (gross margin), operating expenses (operating margin), interest/other items, or taxes. It’s common to fixate on taxes or COGS alone, but net income can drop due to higher SG&A, rising interest costs from more debt, or a one-time loss—even if gross profit looks stable.