Eu bato o ponto às oito.

Yes. In Brazilian Portuguese, eu is often optional because the verb form already shows the subject.

• (Eu) bato o ponto às oito.

Both are natural. Including eu can add emphasis, contrast, or clarity.

For example:

• Eu bato o ponto às oito, mas ele chega mais tarde.
  = I clock in at eight, but he arrives later.

Because bato is the correct verb form for eu in the present tense.

The verb is bater. Its present forms include:

• eu bato
• você/ele/ela bate
• nós batemos
• eles/elas batem

So:

• Eu bato o ponto = correct
• Eu bate o ponto = incorrect
• Eu bater o ponto = incorrect in this sentence, because bater is the infinitive

It is in the present tense, and in a sentence like this it usually describes a habit or routine.

So Eu bato o ponto às oito usually means something like:

• I clock in at eight.
• I normally clock in at eight.

If you wanted to make the routine idea more explicit, you could say:

• Eu sempre bato o ponto às oito.
  = I always clock in at eight.

It is an idiomatic expression in Brazilian Portuguese. It means to clock in, punch in, or more generally register your work time.

Literally, bater often means to hit, so the expression may seem strange at first. But in this context, it does not mean physically hitting a point. It is just the normal workplace expression.

A few similar expressions you may also hear are:

• marcar o ponto
• registrar o ponto

Because ponto is a masculine singular noun, so it can take the definite article o.

• o ponto = the time record / the clock-in record / the time clock entry

In real Brazilian Portuguese, both bater o ponto and bater ponto can be heard. The version with o is completely natural, and the version without the article is also common in everyday speech.

So:

• Eu bato o ponto às oito.
• Eu bato ponto às oito.

Both are used.

Because às is the contraction of a + as.

With clock time in Portuguese, the word horas is understood:

• às oito (horas) = at eight (o’clock)

Since horas is feminine plural, Portuguese uses as, and that combines with a to form às.

Compare:

• à uma = at one
• às duas = at two
• às oito = at eight

The accent mark is important here.

Usually yes: it means at eight o’clock.

In real life, whether it sounds exact or just approximate depends on context, but by itself it normally suggests 8:00.

If you want to say around eight, Portuguese usually says:

• por volta das oito
• mais ou menos às oito

By itself, bater o ponto can refer more generally to registering your work time, so context matters.

In many situations, people will understand Eu bato o ponto às oito as I clock in at eight, especially if eight is the start of the workday. But the expression itself is not limited only to entering.

If you need to be specific, you can say:

• Bato o ponto na entrada às oito.
  = I clock in at eight.
• Bato o ponto na saída às seis.
  = I clock out at six.

Yes. Portuguese allows some flexibility.

These are all natural:

• Eu bato o ponto às oito.
• Às oito, eu bato o ponto.
• Eu, às oito, bato o ponto.

The most neutral version is the original one. Starting with Às oito can give a little more focus to the time.

Yes, bater o ponto is especially associated with Brazilian Portuguese.

In Brazil, it is a very common workplace expression. In other varieties of Portuguese, especially European Portuguese, you may hear different expressions instead.

So if you are learning Portuguese (Brazil), this sentence is very natural and useful.