Have you ever stopped to think about what it really means when a company announces its net profit? I mean, we see headlines in the news saying that Petrobras had a profit of 100 billion and it seems like money falls from the sky. But that's not quite how it works.

Net profit is basically what’s left after the company pays everything. All costs, all expenses, all taxes. It’s the final result, that number that appears on the last line of the income statement. And that’s exactly why investors keep an eye on it.

But here’s the point that many people get confused: revenue is not profit. A company can generate 50 million in revenue and have a much smaller net profit. Why? Because from gross revenue, you deduct salaries, rent, taxes, raw materials, all kinds of costs. Only after subtracting all of that do you find out what the real net profit was.

And there’s one more important thing: net profit is not cash in hand at the moment. Accounting works on an accrual basis, so a company can have positive net profit but still face liquidity problems. That’s why analysts always tell you to also look at cash flow and the balance sheet, not just the isolated net profit.

The calculation is straightforward: you take total revenue, subtract variable costs, subtract fixed expenses, subtract taxes. Done, what’s left is the net profit. There’s a basic formula, but what really matters is understanding that every detail makes a difference.

Now, there’s an indicator that complements this analysis well: net profit margin. It’s basically how much of the revenue turns into profit, in percentage. A company that earns 100 and has a net profit of 20 has a 20% margin. That’s it.

The detail is that there’s no universal ideal margin. It varies a lot by sector. A bank might have a margin of 20-30%, while a retail store works with 1-5%. Technology tends to have higher margins, mining and oil vary greatly depending on commodity cycles.

Looking at the Brazilian market, you can clearly see this difference. Itaú has strong net profit because banks operate with financial spreads. Petrobras is a classic example of volatility in net profit, heavily dependent on oil prices. Vale shows high margins during positive mineral cycles but drops when prices fall. Magazine Luiza works with tight margins typical of retail. Engie has predictable profit because it’s energy. Totvs grows steadily because software benefits from economies of scale.

The point that no one can ignore: before investing in any company, you need to look at net profit along with other indicators. Debt levels, cash generation, sector prospects. It’s not just about grabbing a high net profit number and thinking it’s good. You need context.