Hoje foi um dia agitado, mas agora estou calmo.

Foi is the preterite form of ser for ele/ela/você. In Hoje foi um dia agitado, Portuguese is treating hoje almost like the day today and summarising it as a whole: Today was a hectic day.

This is very natural when you are looking back on how the day has gone.

Both relate to the past, but they do different jobs.

• foi = a completed fact, seen as a whole
• era = a description/background in the past, often more open-ended

So:

• Hoje foi um dia agitado = Today turned out to be a hectic day / Today was a hectic day
• Hoje era um dia agitado would sound odd in most normal contexts

For this sentence, foi is the natural choice because the speaker is summing up the day.

Um means a. So um dia agitado means a hectic day.

Portuguese usually uses the indefinite article here, just as English does:

• Foi um dia difícil = It was a difficult day
• Foi um bom dia = It was a good day

Leaving out um would sound wrong here.

Agitado can mean hectic, busy, chaotic, restless, or agitated, depending on context.

In um dia agitado, the most natural English idea is:

• a hectic day
• a busy day
• sometimes a stressful day

It does not usually mean that the day itself is literally emotionally agitated; it describes the day as full of activity, disturbance, or stress.

Because estar is used for a temporary state, while ser is used for a more permanent characteristic.

• estou calmo = I am calm now
• sou calmo = I am a calm person / I’m generally calm

In this sentence, agora shows a change of state: the day was hectic, but now the speaker feels calm. So estou is exactly right.

Portuguese often leaves out subject pronouns when the verb ending already makes the subject clear.

• estou already means I am
• so (eu) estou calmo is fine with or without eu

In this sentence, omitting eu sounds natural and normal:

• mas agora estou calmo

If you said mas agora eu estou calmo, it would add a bit more emphasis.

Calmo agrees with the speaker’s gender.

• male speaker: estou calmo
• female speaker: estou calma

This is because adjectives in Portuguese often change form depending on gender.

So a woman would say:

• Hoje foi um dia agitado, mas agora estou calma.

Because it describes dia, and dia is a masculine noun in Portuguese.

So:

• um dia agitado

If the noun were feminine, the adjective would usually change:

• uma manhã agitada = a hectic morning

Adjectives normally agree with the noun they describe in gender and number.

Putting Hoje at the beginning is very natural because it sets the time frame immediately: Today...

Portuguese often places time expressions early in the sentence:

• Hoje estou cansado.
• Ontem foi difícil.
• Agora estou melhor.

You could sometimes move it, but Hoje foi um dia agitado is the most straightforward and natural order.

Mas means but. It introduces a contrast:

• Hoje foi um dia agitado = the day was hectic
• mas agora estou calmo = but now I’m calm

So the sentence contrasts the earlier chaos with the speaker’s present state.

Agora means now, and it is important because it marks a change in time and situation.

Without agora:

• Hoje foi um dia agitado, mas estou calmo.

This is still understandable, but agora makes the contrast clearer:

• the day was hectic
• now, at this moment, I am calm

It helps show that the calmness is the speaker’s current state.

Yes, that is a very good translation.

A slightly more natural English version in some contexts might also be:

• Today was hectic, but now I’m calm.
• It was a hectic day today, but now I’m calm.

But the literal translation is perfectly fine and matches the Portuguese well.

Yes. Hoje foi um dia agitado, mas agora estou calmo is perfectly natural in European Portuguese.

It would also be understood in Brazilian Portuguese, though pronunciation and some everyday word choices may differ by region. For this sentence, the grammar and vocabulary are standard and natural in Portugal.

Yes. Agitado can describe both a day and a person, but the meaning shifts slightly with context.

• um dia agitado = a hectic/busy day
• uma pessoa agitada = an agitated/restless person

So in this sentence, because it refers to dia, it means the day was hectic or full of activity, not that the day had emotions.

In European Portuguese, you may hear esteve um dia... in some contexts, especially with weather-like or situational descriptions, but for this sentence Hoje foi um dia agitado is the clearer and more standard way to say Today was a hectic day.

So for a learner, foi um dia agitado is the safest and most natural choice.

You would change the verb and the adjective:

• Hoje foi um dia agitado, mas agora estamos calmos.

If the group is all female, then:

• Hoje foi um dia agitado, mas agora estamos calmas.

The adjective must agree with the people being described.