Irregular verbs

How can we tell if a verb is irregular or not, and what is the difference between a regular verb and an irregular verb?
Thanks in advance.


There’s no real way of knowing other than memorizing/exposure. They are “irregular” because they are conjugated differently than the regular verbs with the same endings.

Example: Dar finishes with AR but isn’t conjugated the same way as Falar. Unfortunately, many of the most commonly used verbs are “irregular”. Off the top of my head: ser, estar, ter, dar, fazer, poder, vir, trazer, ver… The most common ones you end up seeing so often, you just end up memorizing them all through input.


@Kellie.williams, it’s exactly as @tienhung1985 said! You’ll know if a verb is irregular if its conjugations don’t match the standard conjugation patterns for each of the three verb groups (verbs ending in -AR, -ER or -IR). So, you have to at least know how a regular verb of each group would be conjugated, to be able to compare other verbs with it. Verbs don’t have to be irregular in every single tense or grammatical person; many of them have some conjugations that follow a regular pattern and then some others that don’t.

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I think the others explained the concept of a regular or irregular verb pretty well. As @tienhung1985 said, you can’t tell just by looking at the verb; you just have to memorise them. I really like the website to learn and look up verb conjugations. They provide the regular conjugations in black font and the irregular conjugations in orange font. Some verbs like “ser” have irregular conjugations for most tenses but do actually follow the standard rules for some tenses. This website is a quick and easy way to find that information.

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Two sites I like for the conjugations and for definitions in general are:


One difference however, Infopédia does not conjugate the Imperativo Negativo which is slightly different from the Imperativo Afirmativo.