Reading a P&L

In the last lesson we built the revenue → COGS → gross profit → opex → operating profit → net profit chain by hand, for one coffee shop. That same chain, formalised and published, is the income statement. So you already know how to read one — you just haven’t seen it laid out with a real company’s line items yet. That’s all this lesson adds: the standard rows, the subtotals, and the two or three places the interesting questions hide.

Why the P&L is ordered top to bottom

The income statement is not a random list of numbers. It tells a story in a specific direction: start with all the money the business brought in, then subtract costs in order of how directly they tie to delivering the product, and see what survives to the bottom.

Each subtraction answers a different question:

• After paying to deliver the product, what is left? → Gross profit
• After paying to run the business (sales, engineering, admin), what is left? → Operating income
• After paying lenders and the government, what is left? → Net income — the bottom line

That ordering is not arbitrary. By looking at the intermediate lines you can diagnose where money is leaking — is delivery expensive? Is the sales machine eating everything? — without having to read a thousand-page annual report.

A real SaaS P&L, line by line

Below is one year of financials for a hypothetical SaaS company (software-as-a-service — software sold by recurring subscription, like Spotify or Slack).

Costs shown in parentheses are subtractions (a common accounting convention). Now let us walk each line.

Revenue

Revenue (also called sales or top line) is the total money customers paid during the year: $5,000,000. Nothing has been subtracted yet. This is the ceiling from which everything else is carved.

COGS and Gross Profit

COGS (Cost of Goods Sold) is the cost directly tied to delivering each unit of the product. For a SaaS company the main COGS items are cloud hosting fees (the servers that run the software) and customer-support salaries (the people who help users directly). Here: $1,000,000.

Subtract COGS from Revenue and you get Gross Profit — the money left after covering delivery:

$5,000,000 − $1,000,000 = $4,000,000

Gross margin is gross profit expressed as a percentage of revenue:

$4,000,000 ÷ $5,000,000 = 80%

An 80% gross margin is typical and healthy for SaaS. Delivering software to one more customer costs almost nothing (no factory, no raw materials), so most of each dollar of revenue survives past COGS. A grocery chain, by contrast, might have a gross margin of 25% because physical goods cost a lot to buy and move.

Opex — the three buckets

Opex (operating expenses) are the ongoing costs of running the business, not delivering the product. The P&L breaks opex into three standard buckets:

Total opex: $2,200,000 + $1,000,000 + $500,000 = $3,700,000.

Notice that S&M alone ($2.2M) is more than half of gross profit ($4M). This is common in early-stage SaaS — companies spend aggressively on sales to grow fast, betting that the recurring subscription revenue will pay back that investment over many years.

Operating Income (EBIT)

Operating income is what remains after paying both COGS and opex — everything the business needed to operate this year:

$4,000,000 − $3,700,000 = $300,000

Operating income is also called EBIT (Earnings Before Interest and Taxes). Analysts use EBIT to compare the operating performance of companies with different debt loads or tax situations, because it strips those out.

You will also hear EBITDA (Earnings Before Interest, Taxes, Depreciation, and Amortization). Depreciation is the gradual expensing of a physical asset (e.g., a server rack losing value over time); amortization is the same idea for intangible assets (e.g., acquired software licenses). EBITDA adds those back to EBIT to get a rough proxy for the cash the business generates from operations.

Interest, Taxes, and Net Income

Interest is the cost of debt — if the company borrowed money, it pays the lender a fee each year. Taxes are what the company owes the government on its profits. Combined here: $100,000.

Subtract them from operating income to get net income (also called the bottom line or net profit):

$300,000 − $100,000 = $200,000

Net margin is net income as a percentage of revenue:

$200,000 ÷ $5,000,000 = 4%

A 4% net margin means for every dollar of revenue, the company keeps four cents as profit. That is thin. The business is profitable — which is an achievement — but almost all the gross profit gets consumed by the sales machine. Whether that is good or bad depends on strategy: if those sales dollars are buying loyal, long-term subscribers, the bet may pay off.

The waterfall at a glance

Reading margins to judge health

Two ratios do most of the work:

The gap between 80% and 4% is the story: this business delivers software cheaply, but spends almost all the margin on sales. That is a bet on growth, not an error — but you now know to ask “is that S&M spend generating enough new subscribers to justify it?”

When comparing two companies, a higher gross margin gives more room to fund growth or weather a downturn. A higher net margin means more of every revenue dollar becomes actual profit.

In one breath

The income statement (P&L) tells one story top to bottom: start with revenue, subtract costs in order of how directly they deliver the product, and watch what survives. Revenue minus COGS (hosting, support) gives gross profit, whose share of revenue is the gross margin — 80% here, typical of software because one more user costs almost nothing. Subtract opex (the S&M, R&D, G&A buckets) and you reach operating income / EBIT; subtract interest and tax and you reach net income, the bottom line — a thin 4% margin, because the sales machine ate most of the gross profit. EBITDA adds back depreciation and amortisation as a rough cash proxy, but it hides real costs, so never read it without net income. The two ratios that do most of the work are gross margin (how cheaply you deliver) and net margin (how much actually survives).

Practice

A question to carry forward

The waterfall told you this company made $200k on $5M — for the whole year, in hindsight. But a P&L is a photograph of a year already finished. It can’t tell you the thing a founder lies awake over: at what sales volume does the business cross from loss into profit? Net income was positive here, but only barely — sell a little less and that $200k flips negative. Where exactly is the tipping point?

So the question to carry forward is: how many units must you sell to stop losing money — and what moves that number? The next lesson is break-even analysis. It splits costs into fixed and variable, introduces contribution margin (what each sale chips off your fixed-cost pile), and turns the P&L’s static snapshot into a live answer you can steer with price, cost, and volume.