Errar é humano.

Here, errar means to make a mistake or to be wrong.

In other contexts, errar can also mean things like to miss a target or answer, but in Errar é humano, it means making mistakes in a general sense.

Because Portuguese, like English, can use the infinitive as the subject of a sentence.

So:

• Errar = to make mistakes / making mistakes
• é humano = is human

Literally, the structure is very close to To make mistakes is human in English.

This is a very normal construction in Portuguese.

É is the 3rd person singular of the verb ser:

• ser = to be
• é = is

The accent is important because:

• é = is
• e = and

So the accent distinguishes two different words.

Portuguese uses ser for general characteristics, definitions, and essential qualities, and estar for states or conditions.

In Errar é humano, the idea is that making mistakes is part of human nature, so ser is the correct choice.

So:

• é humano = is human / is part of being human

Using estar here would sound wrong.

Here, humano is an adjective.

It means human, not a human.

So:

• humano = adjective: human
• um humano = noun: a human

In Errar é humano, it describes the act of making mistakes as something characteristically human.

Because humano is being used as a predicate adjective, not as a noun.

Compare:

• Errar é humano. = Making mistakes is human.
• Ele é humano. = He is human.

You do not use an article before an adjective in this kind of structure.

If it were a noun, then you might need an article:

• Ele é um humano. = He is a human.

But that is a different meaning.

Yes, É humano errar is grammatically correct.

However, Errar é humano is the much more common and fixed version of the saying. It is the standard proverb, just like the English expression To err is human.

So both are possible, but Errar é humano is the one you are most likely to hear and see.

A rough European Portuguese pronunciation is:

uh-RRAR eh oo-MAH-noo

A few notes:

• The rr in errar is a stronger r, usually a throaty sound in European Portuguese.
• é is pronounced like eh.
• In European Portuguese, unstressed vowels are often reduced, so the first e in errar is not a full clear eh sound.

A more IPA-style version is approximately:

[ɨˈʁaɾ ɛ uˈmɐnu]

Exact pronunciation can vary a bit by region.

It is used in both European Portuguese and Brazilian Portuguese.

Errar é humano is a very common expression across the Portuguese-speaking world. The wording is the same; the main difference is pronunciation.

It is both grammatical and a fixed saying.

It is the Portuguese equivalent of the well-known proverb To err is human, originally from the Latin expression Errare humanum est.

So although the sentence is perfectly ordinary grammatically, people usually recognize it as a set expression.