Fundamentals

Tariffs: What They Are, How They Work, and What Effects They Have

By Daniel Sardá · Published on September 22, 2026

6 min read1,201 words

Tariffs tax imported goods, but their cost does not necessarily fall on one person alone. This guide explains how they are calculated, why they are used, and what effects they can have.

A product crosses a border and, before it enters the market, customs authorities require a payment. That charge is an import tariff: a duty imposed on goods arriving from another country. Although the word “tariff” can also refer to professional or administrative fee schedules, in international trade it has this more specific meaning.

The definition is straightforward. What is less obvious is who ultimately bears the cost, what happens to the selling price, and why a government chooses to impose it. To understand this, it helps to follow the product from the border to the buyer’s final decision.

How a tariff works

When imported goods enter a customs territory, their classification, origin, and, where applicable, customs value are identified. That information determines the duty under the rules of that market. Rates can vary by product, country of origin, and agreements in force, so there is no universal percentage.

Suppose goods have a customs value of 100 monetary units and face a 10% tariff. The calculated duty would be 10. That figure shows what must be paid to customs for that purpose. It does not, by itself, mean the consumer price will rise by exactly 10.

The importer makes the legally required payment under the rules of the jurisdiction. It may then try to pass some of the cost on to the wholesaler, retailer, or consumer. It may also accept a lower margin, negotiate a lower price with the foreign supplier, or replace the product. The response will depend on competition, the availability of alternatives, contracts, and each participant’s bargaining power.

Key idea: The person who hands over the money at customs does not necessarily bear the tariff’s full economic cost.

This distinction between legal liability and economic incidence prevents a common confusion. Saying that “the foreign country pays” or that “the consumer pays it all” turns one possible outcome into an automatic rule. In practice, the cost can be divided in different ways.

Types of tariffs

The type of tariff describes how it is calculated, not why it was adopted. The most common methods are:

• Ad valorem: applies a percentage to the customs value of the goods. In the example above, 10% of 100 produces a duty of 10.
• Specific: sets an amount per physical unit, such as a stated sum per kilogram, litre, or item.
• Combined formula: includes percentage-based and specific components. Some formulas add both; others establish which one applies under particular conditions. Technical terminology may vary, so the relevant rule should be checked.

The World Trade Organization describes tariffs as customs duties on merchandise imports. For percentage-based charges, the way customs value is determined is especially important: the same rate applied to different bases produces different payments.

Why are tariffs imposed?

Governments justify tariffs with several objectives. One is raising public revenue. Another is giving domestic producers a price advantage over similar imported goods. Tariffs can also be used in response to another country’s measures or as a negotiating instrument.

Those purposes should not be confused with outcomes. A tariff can temporarily benefit a protected industry without guaranteeing more net employment or greater welfare for the economy as a whole. It can also raise revenue, but that revenue is a transfer to the state, not automatic proof of a net social benefit.

In sectors considered strategic, supporters may accept higher costs in order to preserve productive capacity. That is a public choice that requires comparing alternatives and recognizing who receives the benefit and who bears the cost; protection should not be presented as cost-free.

Key idea: Protecting one sector can concentrate visible benefits among its producers while dispersing less visible costs among many buyers and businesses.

Effects on consumers, businesses, and the state

The first direct effect is a gap between the cost of bringing the imported good into the market and the price it would have without the duty. From there, several responses are possible:

• Consumers: may pay more, switch brands, substitute the product, or reduce consumption. The impact varies with the importance of the good in their budget and the alternatives available.
• Importers and retailers: may pass on the cost, absorb part of it through lower margins, or reorganize their suppliers.
• Domestic producers: may face less pressure from imported goods and raise sales or prices. However, if they use taxed foreign inputs, their own costs can also rise.
• The state: receives tariff revenue, although the amount depends on the value of imports and on how demand changes.
• Exporters and trading partners: may lose competitive access to the affected market. If the other government retaliates, exporters in the country that initiated the measure can also be harmed.

The final distribution never depends only on the percentage written into the rule. A company with few competitors may be able to pass a larger share into its price. In a market with abundant substitutes, the importer or foreign supplier may absorb more to avoid losing sales. Serious analysis therefore examines prices, margins, quantities, and substitution instead of assuming full pass-through.

From the perspective of economic freedom, the central issue is that a tariff changes the voluntary choices involved in international trade and favors some uses of resources over others through political decision-making. That does not erase the public purposes that may be invoked, but it does require their trade-offs to be made visible and opaque privileges to be avoided. Stable, predictable rules at least allow households and businesses to plan with less uncertainty.

Tariffs and non-tariff barriers

Not every restriction on exchange is a tariff. A quota limits the quantity that may be imported; a licence requires authorization; a health or technical standard sets conditions a product must meet. These measures can make market access more difficult, but they do not work like a customs duty calculated on value or quantity.

The distinction matters because not every non-tariff measure pursues economic protection. Some address legitimate health, safety, or information objectives. An assessment should consider whether a rule is necessary, proportionate, and applied without disguised discrimination, rather than grouping distinct instruments under one label.

International trade agreements can reduce or eliminate tariffs among their participants. Preferential treatment, however, often depends on the product, its origin, and the agreed rules. The fact that two countries have an agreement does not mean every good automatically enters duty-free.

Key idea: To identify the actual tariff on an import, one needs at least the product, origin, destination, and applicable agreement.

How to assess a tariff measure

A clear discussion of tariffs should ask four questions: What objective is being pursued? Who pays at the border? How might the cost be distributed? What alternatives are available? It should also account for effects on inputs, exporters, and possible responses from other governments.

The announced percentage is only the beginning of the analysis. A tariff is a border tax with distributive effects: it can raise revenue and protect certain producers, but it can also change prices, margins, and purchasing decisions. Understanding that chain makes it possible to debate each measure by its likely results and real costs, not only by the intention with which it was presented.