I just noticed that many people are still confused about the P&L Statement, also known as the profit and loss statement. Actually, it’s not difficult at all—once you understand the basic principles, it becomes much easier.

Let’s start with the simplest part: P&L is a document that shows whether our business made a profit or a loss during a specified period. The formula is very simple: total revenue minus total expenses. If the result is positive, it’s a profit; if it’s negative, it’s a loss.

But what’s interesting is that the P&L doesn’t just tell you whether you made a profit. It also indicates where the profit comes from and which expense items should be reduced. If you understand this, it can help with business planning a great deal.

For example, the Bank of Thailand in 2565 had income from 5 sources: interest income, gains from the sale of investments, fees, and other income. Once you know where the income comes from, you can decide which areas to focus on more.

When talking about the Profit and Loss Statement, you also need to understand profit at each stage. Start with gross profit (Gross Profit), which is revenue minus the cost of goods sold—showing by how much the product’s selling price is higher than the cost. Then come operating profit (Operating Profit), which deducts general expenses. Finally, net income (Net Income) is the real profit after everything has been deducted.

There are two P&L formats. The first is the Report Form, which is organized from revenue down to profit, making it easier to read. The second is the Account Form, which is shown like a “T” account, with expenses on the left and income on the right. Both formats are useful—they just present the information differently.

The most important thing is to read the P&L and understand it correctly. First, check the period it covers, because P&L can be prepared monthly, quarterly, or annually. Next, look at whether it shows a profit or a loss. If revenue is higher than expenses, it’s a profit; if it’s lower, it’s a loss.

Then, look at the sources of revenue, because revenue may come from several places. Some may come from the core business, while others may come from supplementary income. Knowing what proportion each source accounts for helps you analyze whether the business is stable. And lastly, you should review expenses as well, because if expenses are too high, you need to find ways to reduce them so that profit can increase.

The importance of the P&L is not only that it shows profit and loss—it also helps measure financial performance. It provides information for analyzing financial conditions, indicates the ability to generate profits, and supports strategic planning. Both investors and executives use P&L as a tool for making business decisions.

But remember: the Profit and Loss Statement is only one part of analysis. When making investment decisions, you shouldn’t consider only the P&L—you should also look at other factors, such as the type of business, the quality of the management team, and the industry’s growth trends. By understanding the P&L deeply, we can become smarter investors and make more careful decisions.