The Three Conjugation Classes (-ar, -er, -ir)

Every Portuguese verb in its infinitive form ends in one of three suffixes: -ar, -er, or -ir. These endings define the three conjugation classes, and each class follows its own set of patterns across every tense and mood. Once you know which class a verb belongs to, you already know most of what you need to conjugate it.

The first conjugation: -ar verbs

The -ar class is by far the largest. Roughly 60-65% of all Portuguese verbs belong to this group, and nearly every new verb that enters the language joins it. This is the class to learn first — it gives you the biggest return on your effort.

Most -ar verbs are regular, which means that once you memorise the endings for falar, you can conjugate hundreds of other verbs the same way.

The second conjugation: -er verbs

The -er class is smaller than -ar but contains many essential everyday verbs. You will encounter -er verbs from your very first conversations.

Notice that fazer appears in the list above — it is one of the most common verbs in Portuguese, but it is irregular. The -er class contains a higher proportion of irregular verbs than the -ar class.

The third conjugation: -ir verbs

The -ir class is the smallest of the three, yet it includes many high-frequency verbs that you will use daily. In several tenses, -ir verbs share their endings with -er verbs, which lightens the memory load.

Both ir (to go) and vir (to come) are among the most irregular verbs in Portuguese, but they are so common that you will learn them by sheer repetition.

Present indicative endings side by side

The table below compares the regular present indicative endings for all three classes, using falar, comer, and partir as model verbs.

Key patterns to notice:

• The eu form ends in -o in all three classes — no exceptions for regular verbs.
• The -er and -ir classes share the same endings except in the nós form (comemos vs partimos).
• The -ar class stands apart with its distinctive a vowel (falas, fala, falamos, falam).

How to identify a verb's class

Identifying the class is the simplest step in conjugation: just look at the last two letters of the infinitive.

• Ends in -ar → first conjugation (e.g. comprar, chegar)
• Ends in -er → second conjugation (e.g. viver, correr)
• Ends in -ir → third conjugation (e.g. abrir, sentir)

This habit becomes second nature very quickly. Every time you encounter a new verb, glance at the ending and you immediately know which set of patterns to apply.

Which class has the most irregulars?

The -ar class is the most predictable. The vast majority of -ar verbs are completely regular — the irregularities tend to be minor spelling adjustments (like ficar → fiquei) rather than deep changes to the stem.

The -er and -ir classes have proportionally more irregular verbs. Some of the most important verbs in Portuguese — ser, ter, fazer, poder, dizer, ir, vir — are irregular -er or -ir verbs. Do not let this discourage you: these verbs are so frequent that you will practise them constantly.

New verbs default to -ar

When Portuguese creates a new verb — whether by borrowing from another language or coining a word for a new concept — it almost always enters the language as an -ar verb.

Words like clicar (to click), googlar (to google), and tweetar (to tweet) all follow regular -ar patterns. This means the -ar class is not only the largest today but also the one that keeps growing.

The special case of pôr

There is one verb family that does not fit neatly into any of the three classes: pôr (to put). Historically, pôr comes from the Latin ponere, an -ere verb, and it is sometimes called a "fourth conjugation." In practice, pôr and its compounds follow -er patterns with modifications.

Common compounds of pôr:

The main compounds include compor (to compose), dispor (to arrange), propor (to propose), supor (to suppose), and expor (to expose). They all conjugate like pôr. You will study these in detail later — for now, just be aware that this small family exists outside the standard three classes.

Portuguese shares this system with other Romance languages

The three-conjugation system is not unique to Portuguese. Spanish, Italian, and French all inherited the same structure from Latin. If you already speak another Romance language, you will recognise the logic immediately. The endings differ, but the principle — group verbs by their infinitive suffix and apply class-specific patterns — is the same everywhere.

With these three classes clearly in mind, every tense and mood you learn from here will follow the same organising principle. Start with the regular -ar verbs, then move on to -er verbs and -ir verbs as you build confidence.