How to Read an Income Statement (P&L)

If a stock is a business, then the income statement is its school report. It tells you what the company sold this term, what it spent on books and dinners, and whether it ended the year with anything left over.

For most UK investors, this is the financial statement you will look at first and most often. It also goes by another name on this side of the Atlantic, the profit and loss statement (or "P&L"). Whether your broker or company report calls it an income statement or a P&L, it is exactly the same document.

Once you can read one, the rest of investing gets a lot easier. You stop relying on a single P/E ratio and start understanding why the price is what it is.

An income statement is one of the three main financial statements every public company has to publish. It shows the company's financial performance over a period of time, usually a quarter or a full year. It tells you how much money came in, how much went out, and what was left.

To put it in context, the three statements answer three different questions:

An income statement is essentially a waterfall. Money pours in at the top as revenue, then a series of costs are subtracted on the way down, until what is left at the bottom is profit. Each line answers a different question.

Here is the structure you will see on almost every P&L statement, top to bottom:

Each line in plain English

• Revenue — every pound or dollar a customer paid the company for goods or services. This is before any costs. UK companies often label this "turnover."
• Cost of goods sold (COGS) — the direct cost of producing whatever they sold. For Apple, that is the cost of building an iPhone. For Tesco, the cost of the food on the shelves. For a software company, mostly the servers and support staff that make the product run.
• Gross profit — what is left after the direct cost of the product. This tells you how much "raw" profit the product itself generates before head office gets involved.
• Operating expenses — everything it takes to run the business around the product: research and development (R&D), sales and marketing (S&M), and general and administrative costs (G&A). Salaries, rent, advertising, the lot.
• Operating income (or EBIT — earnings before interest and tax) — what is left after running the whole business but before paying lenders and the taxman. This is the cleanest measure of operating performance.
• Interest expense — what the company pays its lenders. Heavily indebted companies have a big number here. Apple barely has one. Some property and utility companies have eye-watering ones.
• Tax — what HMRC, the IRS or whichever overseas authorities take. Tax rates vary wildly by country and by year, which is one reason investors look at pre-tax measures too.
• Net income — the bottom line. This is "profit" in the traditional sense. It is also the "E" in P/E ratio and the numerator in earnings per share.

Once you have walked down the waterfall, the next move is to convert the absolute numbers into margins. A margin is just a profit number divided by revenue, expressed as a percentage. Margins let you compare a £69 billion supermarket to a $416 billion technology company without your eyes glazing over.

There are three margins worth memorising:

Margins differ wildly by industry

Comparing a supermarket's net margin to a software company's is like comparing the goalkeeper's goal tally to the striker's. They are doing different jobs. Have a look at three real businesses from FY2025:

Once you have the basics, you will quickly run into three acronyms management teams love throwing around. They are not magic, but each one tells you something slightly different.

"Adjusted" earnings: read the small print

Most companies now report two versions of profit: the official one (GAAP in the US, IFRS in the UK and Europe) and an "adjusted" or "non-GAAP" version that strips out things management does not want you to focus on, like share-based compensation, restructuring charges or acquisition costs.

Knowing the lines is one thing. Reading them like an investor is another. When we look at a P&L for the first time, we are not really after the absolute numbers — we are after a story. Here is the order we run through it.

Peter Lynch wrote that the most important thing he looked at on an income statement was whether earnings were growing — and whether the growth was for the right reasons. We agree, with the small addition of "and whether margins are heading in the right direction."

A clean P&L does not guarantee a great investment. But a messy one is a fantastic warning sign. Here are the patterns we treat as red flags whenever we see them:

Theory is nice. Working through a real income statement is better. Let's take Apple's full-year 2025 numbers because most readers either own an iPhone, hold AAPL inside a US ETF, or both.

Now do the investor read-through:

• • Revenue of $416bn. That is roughly £325bn — bigger than the entire output of many small countries. For context, every UK FTSE 100 company combined would not match it.
• • Gross margin of 47%. Extraordinarily high for a hardware business. The reason is the mix shift toward services (App Store, iCloud, advertising) which are software-margin businesses bolted on to the iPhone customer base.
• • Operating margin of 32%. One of the highest in the world for a company of Apple's size. They spend roughly 15% of revenue on R&D and SG&A combined, leaving the rest as operating profit.
• • Net margin of 27%. Apple keeps roughly 27 cents of every dollar of sales after every cost is paid. Tesla, by comparison, kept around 7 cents in 2025, and Tesco around 2p.
• • EPS. With around 14.9 billion shares outstanding, EPS comes out at roughly $7.50. At a $260 share price that is a P/E of about 35x — a premium multiple, justified (or not) by the expectation that those margins keep compounding.

This is what a high-quality earner looks like. The red flags above are conspicuously absent: gross margin is rising not falling, operating expenses are growing slower than revenue, share count is gradually shrinking thanks to buybacks, and there are no recurring "one-off" items.

Once you have done this exercise once, you can do it on any company in 10 minutes. Try it next on a UK name you know — Diageo, AstraZeneca or Tesco are good starters because their annual reports are accessible and the numbers are big enough to be interesting. If you need a refresher on putting these numbers into valuation context, our P/E ratio guide takes the "E" you have just calculated and shows you how to think about the "P."

UK and most European companies report under IFRS (International Financial Reporting Standards). US companies report under US GAAP (Generally Accepted Accounting Principles). They are two different sets of accounting rules, and for the purposes of reading an income statement, the differences are smaller than they sound.

A few practical points worth knowing:

• • Different vocabulary. UK reports say "turnover" instead of "revenue," "profit before tax" instead of "pre-tax income," "finance costs" instead of "interest expense." The lines do the same job.
• • Operating profit categorisation. IFRS gives companies more flexibility about what counts as "operating" versus "non-operating." US GAAP has tighter rules. This is one reason adjusted/underlying figures are popular in UK reports.
• • Inventory accounting. US GAAP allows the LIFO ("last in, first out") inventory method; IFRS does not. For most retailers and manufacturers this can cause small differences in COGS.
• • R&D capitalisation. IFRS allows certain development costs to be capitalised on the balance sheet rather than expensed; US GAAP almost always expenses them.

These nuances matter if you are a forensic accountant. For the average UK investor reading a P&L for the first time, do not worry about them. Focus on the trend in revenue, the trend in margins, and whether the bottom line is real cash or accounting noise.

You do not need a Bloomberg terminal to read an income statement. The same numbers companies show their auditors are free for anyone who looks. Here is where we go:

For quick comparisons across many years, free sites like Yahoo Finance, Stock Analysis and Macrotrends give you 5-10 years of income statement data in a single table. That is usually our starting point before going to the source documents for the detail.

If you want to skip the manual lift entirely, that is exactly what StockRocket does. Pop in a ticker, and the AI summarises the P&L, flags the margin trend and surfaces the items most worth a second look. For learning, though, there is no substitute for reading at least a few annual reports yourself. It is the difference between watching football and actually playing it.

The income statement (or P&L) is the single most useful page in any annual report. Once you can read it, you stop guessing whether a stock is "a good business" and start knowing.