Revenue, Cost & Profit

The last lesson ended on a deceptively simple question: is revenue the same as profit? The owner above already knows the answer is no — $20,000 came in, and almost none of it stayed. This lesson is the map that explains where the rest went.

Every analyst, founder, and investor reads a business from that same map: money flows in at the top, costs get subtracted one layer at a time, and whatever survives is profit. The map has names — revenue, COGS, gross profit, opex, operating profit, net profit — and once you have the vocabulary, you can read any business in minutes.

Let’s walk one month of a single coffee shop and define every term the moment it shows up.

Revenue — the top line

Revenue (also called sales or top line — because it sits at the very top of every financial report) is the total money a business receives from selling its product or service before any costs are taken out.

For our coffee shop:

• Price per coffee: $4.00
• Coffees sold in the month: 5,000
• Revenue = $4.00 x 5,000 = $20,000

That’s it. No costs subtracted yet. Revenue is purely money in from customers.

COGS — the cost of each sale

COGS stands for cost of goods sold: the direct cost to produce each unit that was sold. For a coffee shop those are the ingredients that go into every cup.

• Beans + milk + cup per coffee: $1.20
• 5,000 coffees sold
• COGS = $1.20 x 5,000 = $6,000

COGS scales with volume. Sell twice as many coffees and COGS roughly doubles. That’s what makes it a “variable” cost — it moves with output, unlike a fixed cost such as rent, which stays the same no matter how much you sell.

Gross profit and gross margin

Subtract COGS from revenue and you get gross profit: what’s left after paying for the things you actually sold.

Gross profit = Revenue − COGS = $20,000 − $6,000 = $14,000

Analysts usually express this as a percentage called gross margin — where margin means a profit figure expressed as a fraction of revenue, so you can compare businesses of different sizes.

Gross margin = Gross profit ÷ Revenue = $14,000 ÷ $20,000 = 70%

A 70% gross margin means every dollar of revenue leaves 70 cents to cover everything else (rent, staff, taxes) and still turn a profit. High gross margins give a business room to breathe; thin ones leave almost nothing for the layers below.

Operating expenses (opex) — the fixed running costs

So far we’ve only subtracted the cost of making the coffee. But the shop has other bills that come in every month regardless of how many cups are sold.

Operating expenses (opex) are the recurring costs of running the business that do not scale directly with each unit sold.

Whether the shop sells 5,000 coffees or 4,000, rent is still $4,000. That fixed nature is the defining feature of opex.

Operating profit — what the business actually earns from operations

Operating profit (also called EBIT — earnings before interest and taxes — in formal accounting) is gross profit minus opex. It answers: after paying to make the product AND to run the business, how much is left?

Operating profit = Gross profit − Opex = $14,000 − $12,000 = $2,000

Out of $20,000 in sales, only $2,000 survives after production costs and running costs. That is a thin margin — and it explains exactly why the owner said “we barely made money.”

Net profit — the bottom line

Net profit (the bottom line — because it sits at the very bottom of the report) is what remains after every single cost, including interest on loans and income taxes.

For this simplified example, we will skip interest and taxes to keep the numbers clean. In that case:

Net profit ≈ $2,000

Net margin = Net profit ÷ Revenue = $2,000 ÷ $20,000 = 10%

A 10% net margin means the shop keeps 10 cents of every dollar it brings in. In the real world, tax and debt service would push this lower.

The full picture — one bar, three layers

The diagram below shows where the $20,000 goes. Every dollar of revenue is split across three destinations: COGS, opex, and profit. The revenue bar on the left splits into those three pieces on the right.

Key intuitions to lock in

• Revenue is the top line — money in, before any deductions.
• COGS scales with every sale; opex is mostly fixed.
• Gross margin (here 70%) is the breathing room above operating costs.
• Operating profit is the number that shows whether the core business is viable.
• Net profit (the bottom line) is what remains after everything — taxes, interest, all of it.
• The gap between top line and bottom line is filled entirely by costs. Understand the costs and you understand the business.

Vocabulary recap

In one breath

A business is a stack, read top to bottom. Revenue ($20,000) is money in before any cost. Subtract COGS — the per-unit cost of what you sold ($6,000) — and you get gross profit ($14,000), which as a percentage of revenue is the gross margin (70%). Subtract opex — the fixed running costs that don’t move with each sale, like rent and wages ($12,000) — and you get operating profit ($2,000), the number that says whether the core business actually works. Take out interest and tax and you reach net profit, the bottom line. The whole gap between top line and bottom line is just costs, layer by layer — which is why record revenue and a real loss can sit in the very same month.

Practice

A question to carry forward

We just built that revenue-to-profit stack by hand, one subtraction at a time, for a single coffee shop. But every real company — the corner bakery, Apple, the startup down the road — has to report exactly this stack, every quarter, on one standardised page. They don’t get to invent their own layout.

So the question to carry forward is: what does this map look like when it’s a formal, published document with real-company line items on it? The next lesson reads a full income statement (the P&L) top to bottom — the same revenue → COGS → gross profit → opex → operating profit → net profit chain you now know, but with the rows, subtotals, and footnotes an analyst actually meets in the wild, and the two or three places companies quietly hide bad news.