Taxes on purchases and sales: general principles

Taxes on purchases and sales: general principles

When a business buys and sells goods or services, every commercial transaction brings an invisible companion: tax. Far from being a minor detail, the taxes that cross a company's purchases and sales shape the way transactions are recorded, the amount recognized as income, the amount recognized as cost, and even the way cash is managed. In this lesson we will look at the general principles that explain how taxes coexist with the accounting of a business that buys and sells, without referring to any particular country: rates, tax names and procedures change from one place to another, but the underlying accounting logic is very similar almost everywhere. Understanding that logic will help you read financial statements with better judgment, review any invoice with fresh eyes, and talk to your accountant on much firmer ground.

The tax you collect on your sales does not belong to you

The central idea of this whole lesson fits in one sentence: the sales tax you charge your customers is not yours. When your business sells a good or a service, the price the customer pays includes, on top of the value of the product, a component that belongs to the government. Your company then acts as a collector: it receives the money, keeps it separately in its books, and later hands it over to the tax authority. If you thought that component was extra profit, this is the moment to correct that idea, because treating the tax you collect as your own income is one of the most expensive accounting mistakes a small business can make.

The accounting consequence of that idea is immediate: at the very moment of the sale, an obligation is born, in other words, a liability. The typical account that records that obligation is called tax payable, and it represents the amount the business owes to the tax authority for the taxes it collected on its sales. Notice the detail: the obligation does not arise when the tax is paid, but at the instant the sale takes place. That is why the entry is made right away, without waiting for the periodic return or the payment. Every sale generates, at the same time, sales income, an inflow of cash or a right to collect, and a liability for the tax passed on to the customer.

In practice, many companies confuse this point and record the sale for the total amount received, as if everything were income. Months later, when the return is due and the tax must be paid, the obligation was never recorded and the money is already gone. Organized accounting avoids that surprise: if from the very first day the tax collected is kept in its own liability account, the business knows how much belongs to the tax authority and can set it aside. This principle of separation is the foundation of everything that follows, and it should be present in every sales entry you make, no matter how small the transaction.

The tax charged on your purchases may be creditable

Just as tax appears on sales, it also appears on purchases. When your business buys merchandise, raw materials, tools or services from a formal supplier, the invoice includes a tax that the supplier passes on to you. What does your company do with that tax? The answer depends on one central concept: the possibility of offsetting it. If the business is subject to the tax regime and carries out taxable transactions, the tax charged on its purchases may be creditable, which means it can be subtracted from the tax that the business itself generates on its sales for the same period.

In accounting terms, a creditable purchase tax is not added to the cost of the merchandise and is not treated as an expense: it is recorded in its own account that represents a right, that is, an asset. That account is often called input tax or recoverable tax, depending on the country and the chart of accounts in use. That asset is later offset against the liability for the tax generated on sales. When the purchase is recorded, the typical entry recognizes three elements at the same time: the merchandise entering inventory, the creditable tax entering as an asset, and the debt to the supplier for the total amount of the invoice.

However, not every buyer can claim that credit. Someone who buys as a final consumer, without being registered under the tax regime, does not generate taxable sales against which to offset anything, and that is why the tax on those purchases ends up being part of the cost of the good or service acquired. The possibility of offsetting is tied to the condition of the buyer and to the use given to what was purchased, not to a whim of the seller. So before recording a purchase, it is worth asking: can my business offset this tax, or is this amount part of the cost? That question is answered with accounting judgment, knowing the regime the business is subject to and the use that will be given to the merchandise acquired.

The mechanics: what is creditable is subtracted from what was collected

Once you understand that sales generate tax payable and that purchases can generate creditable tax, the natural question is how the two come together. The general mechanics are simple, and they are worth learning by heart. In each period, the business adds up the tax generated on its sales. From that total it subtracts the creditable tax recorded on its purchases for the same period. If what was generated is greater than what is creditable, the difference is paid to the tax authority. If the creditable amount is greater, a balance in favor of the business remains, which can be offset in later periods or claimed as a refund, depending on what the local rules provide. The whole exercise is done without mixing the tax with the price of the goods: each one runs on its own track.

It is important to understand that the tax is not paid transaction by transaction. The business does not pay the tax authority for every individual sale: it accumulates the taxes from all its operations during a period and files a periodic return in which it settles the difference. That means the accounting must keep a day-to-day record of two flows: how much tax has been generated on sales and how much creditable tax has accumulated on purchases. If those controls do not exist, when the return is due the business has no reliable way of knowing how much it owes, and it ends up paying too much or exposing itself to penalties that a simple, timely entry could have avoided.

This offsetting mechanism is the heart of value added tax and its equivalents in other countries. The chain works like this: each link in the production chain pays only the difference between what it collected and what it was allowed to offset, so the tax travels with the good along the entire journey without piling up as a cost for businesses subject to the regime. At the end of the chain stands the final consumer, who offsets nothing and bears the full weight of the tax. Understanding that chain helps you understand why formality matters so much: a link that buys without an invoice breaks the mechanism and ends up carrying taxes it cannot offset, or assuming costs it should never have.

Why the tax is neither income nor expense

One of the most frequent questions in accounting courses is why sales tax does not appear as income or as expense in the income statement. The answer summarizes everything said so far: because the tax does not belong to the business. If the tax collected on sales were treated as income, profit would appear inflated, and the business would end up paying taxes on earnings and distributing dividends on money that in reality must be handed over to the tax authority. If the tax paid on purchases were treated as an expense, profit would appear reduced by an amount that, being creditable, does not represent a final sacrifice but a right to offset.

That is why accounting says the tax cancels itself out. What is generated on sales accumulates in the liability. What is creditable accumulates in the asset. And when the period is settled, the two meet: the asset is used up against the liability, and only the difference reaches the tax authority or remains in favor of the business. Neither the sales income nor the cost of goods sold includes that component when the tax is creditable: sales are recognized net of the tax passed on, and purchases are recognized net of the creditable tax, so that the income statement reflects only the real economic activity of the business, without tax noise.

This separation also helps you read financial statements with judgment. When you see a liability for taxes payable on the balance sheet, you know that money is not available to the business: it has an owner, and that owner is the tax authority. When you see an asset for creditable taxes or for balances in your favor, you know it is a right that will be realized through offset or refund. Looking at tax with those eyes turns a topic that seems technical into a tool for managing cash better: a business that does not set aside the tax it collects sooner or later discovers that it has nothing left to pay it with, and that is one of the most common causes of liquidity problems in small companies.

Selling to final consumers and buying from formal suppliers

It is worth pausing for a moment on the two ends of the chain, because they are the cases most often seen in small businesses. When you sell to a final consumer, that is, to a person or entity that will not offset the tax, your business charges the tax as part of the price and later must pay it to the tax authority: in that transaction the company is only an intermediary between the customer and the government. When you buy from a formal supplier who issues an invoice, the supplier passes the tax on to you, and your business, if it is subject to the regime, records it as creditable: in that transaction your company is the link that can indeed offset. The two roles are different, and it pays to keep them clear.

Between those two ends there is an asymmetry that every business owner should know. On the sales side, the tax you collect must almost always be paid, no matter who you sell to. On the purchases side, the tax is recovered only if the supplier is formal, issues the proper supporting document, and the buyer is in a position to offset it. From that asymmetry comes a practical rule worth repeating: always buy with an invoice when you can. Buying without a receipt may look cheaper at the moment, but it hides the tax that can never be offset and leaves the business without the evidence that the rules require to exercise its rights.

There is also a financial consequence that is often overlooked: the moment when the tax is paid does not always match the moment when it is collected. A business can sell on credit, collecting the tax along with its receivables months later, and still must file its return and pay on the dates set by the rules. It can also buy for cash, paying the creditable tax immediately, and only recover it when the period is settled. That difference in timing forces careful cash planning: tax is not an abstract accounting problem, it is a real cash outflow that must be included in the budget of the business.

Taxes on profits

So far we have talked about the tax that accompanies every purchase and every sale. But there is another large family of taxes that coexists with accounting: those that tax the profit of the business, that is, the result left after subtracting all the costs and expenses of the period from income. The logic of these taxes is different. They are not born in each transaction; they are calculated on the basis of the result obtained, and that is why they are determined after the profit of the period is known, once the accounting has brought together all its income, costs and expenses and can say how much the business earned.

The accounting principle is clear: the tax on profits is recognized in the same period in which the profit that gives rise to it is earned, even if the payment comes later. To achieve that, at the end of the period the business estimates the tax that will correspond to the profit obtained and records two things at the same time: a tax expense in the income statement and a tax payable liability on the balance sheet. That entry is called a provision, and it plays the same role as the tax payable on sales: recognizing the obligation when it arises and not when it is paid. In this way, the income statement of the period reflects the tax cost of having earned that profit.

It is important to note that the base on which the tax on profits is calculated is not exactly the accounting profit. The rules of each country allow certain items to be subtracted and require others to be added, so the taxable base is built by adjusting the profit shown by the accounting records. That is one of the reasons why the calculation of the tax on profits is almost always done or reviewed by an accountant: it is not enough to apply a simple computation to the accounting profit. What accounting guarantees is that a reliable result exists, measured with uniform criteria and backed by supporting documents, from which that base can be built with confidence.

The invoice: the document that makes the offset possible

Throughout this lesson we have mentioned the invoice many times, and the moment has come to give it a section of its own. The invoice is the document that backs the transaction and, in tax matters, it is the key that opens the door to the credit: without an invoice there is no creditable tax, and without creditable tax the tax on your purchases becomes a cost. That is why the first question someone who receives a purchase should ask is not only how much was paid, but which document supports the transaction and whether that document contains the information that the local rules require for the tax to be offset.

A properly issued invoice identifies the seller and the buyer, describes the good or service, separates the value of the transaction from the tax passed on, and meets the formal requirements established by law. Receiving complete invoices and filing them in an orderly way is not bureaucracy: it is the condition for exercising the right to offset and the evidence the business will present if the tax authority reviews its returns. The invoice file is, together with the inventory card and the general journal, one of the records that any business that buys and sells must take care of, and a good accounting practice is to reconcile them with one another: the merchandise entering the inventory card, the invoice arriving from the supplier and the entry in the journal must tell exactly the same story.

The typical entry for each moment of the transaction

To close the practical part, it is useful to summarize in a table the typical entries for each moment of the transaction. Remember that the exact names of the accounts may vary from country to country and from one chart of accounts to another; what matters is the logic: identifying which accounts are debited, which accounts are credited, and why, in each scenario.

Notice that in the sales entry the tax never touches the income account, and in the purchase entry the creditable tax never touches the inventory account or the expense accounts. Each amount travels to the account that matches its nature: what is collected for the tax authority goes to the liability, and what the business has the right to offset goes to the asset. That discipline keeps the income statement from showing income or costs that are not real.

Myths and realities about tax on purchases and sales

To finish, there is nothing better than breaking down the most common myths that circulate among business owners. The following table contrasts what many people believe with what accounting logic shows when it is applied to the reality of each transaction.

Key takeaways

Before closing the lesson, let us review the central ideas in a short list, because they are the ones that should stay with you to apply in the day-to-day life of the business.

• The tax collected on sales is a liability, not income: it is collected for the tax authority.
• The tax paid on purchases can be a creditable asset when the business is subject to the regime and has the corresponding invoice.
• In each period the creditable amount is subtracted from what was collected, and only the difference is paid or remains in favor of the business.
• The invoice is the document that enables the credit: without it, the tax on the purchase becomes a cost.
• The tax on profits is recognized in the period in which the profit is earned, through a provision, even if the payment comes later.

This lesson is part of the accounting manual of Kardex Tauro, a series designed so that a business owner understands the logic behind every entry and can talk to an accountant on equal terms. Remember that rates, rules and procedures vary by country and change over time; this lesson only presents general principles and does not constitute tax advice. Consult your accountant or the rules in force before applying these criteria to your own case, and always check how taxes are named and how they work in the place where your business operates.