The concept
The profit and loss statement (P&L, also called the income statement) summarizes what a business earned and spent over a period: a month, a quarter, a year. It flows from the top (revenue) through layers of cost to the bottom (net profit). Each layer answers a different question: is the core product profitable, is the business profitable after running costs, is it profitable after financing and tax.
Why it matters
Operators who read only their bank balance confuse cash with profit and cannot tell whether a slow month is a timing issue or a structural one. The P&L separates the two and shows where money is actually going.
The standard layout
| Line | What it includes |
| Revenue | Sales of products and services, net of refunds and discounts |
| − Cost of goods sold (COGS) | Direct costs of delivering what was sold: materials, payment fees, contractor delivery time, hosting per customer |
| = Gross profit | What is left to run the business |
| − Operating expenses | Rent, salaries, software, marketing, insurance, professional fees |
| = Operating profit | Profit from running the business |
| − Interest, + other income | Loan interest, bank interest |
| = Profit before tax | |
| − Tax | Income tax expense (if the entity pays its own) |
| = Net profit | The bottom line |
Worked example
A small online course business, one month:
| Revenue | 18,400 |
| COGS (payment fees 3%, platform fees, contractor support) | (2,760) |
| Gross profit | 15,640 (85%) |
| Marketing | (4,200) |
| Software subscriptions | (1,100) |
| Owner salary | (6,000) |
| Accounting and insurance | (650) |
| Operating profit | 3,690 (20%) |
Reading it: the product itself is highly profitable (85% gross margin). The business keeps 20 cents of each revenue dollar after running costs. Marketing is the largest controllable expense; if revenue fell 20% with marketing unchanged, operating profit would roughly reach zero. That sensitivity is visible only because the layers are separated.
Reading a P&L well
- Look at gross margin % first. It tells you whether the product works.
- Compare each expense line to the same month last year and to the last three months. Trends matter more than single months.
- Express every line as a % of revenue. This makes months of different size comparable.
- Ask what is missing. An owner who takes no salary has an understated cost base.
Common mistakes
- Treating owner draws as expenses when they are distributions, or omitting an owner salary entirely so profit looks better than it is.
- Putting direct delivery costs in operating expenses, which inflates gross margin.
- Reading one month in isolation. Seasonality and timing swamp any single period.
- Mistaking a profitable P&L for available cash. The next two lessons explain why they differ.
Action Step
Pull your last three months of P&L from your accounting software or build one from bank data. Reclassify so direct delivery costs sit in COGS. Add a column expressing each line as a percent of revenue, and write down your gross margin % and operating margin % for each month.