Learn Hardcore Portuguese (Portugal): Eu quero ficar na cama hoje.

Eu quero ficar na cama hoje. – perfectly correct, a bit more explicit/emphatic.
Quero ficar na cama hoje. – also perfectly correct and very natural.

You normally include eu:

to emphasize I (as opposed to someone else):
Eu quero ficar na cama hoje, tu é que tens de ir trabalhar.
“I want to stay in bed today, you’re the one who has to go to work.”
or in contexts where it might otherwise be unclear who is being talked about.

In ordinary neutral sentences, Quero ficar na cama hoje is often what you’ll hear in Portugal.

Why is it quero ficar and not quero de ficar or quero a ficar?

With querer meaning “to want”, the pattern in Portuguese is:

querer + infinitive (no preposition)

So you say:

quero ficar – “I want to stay”
quero comer – “I want to eat”
queremos sair – “we want to go out”

You do not add de, a, or any other preposition between querer and the infinitive in this meaning.

Using de here would sound wrong to a native speaker:

✗ quero de ficar – incorrect
✓ quero ficar – correct

What exactly does ficar mean here? Why not estar?

Ficar has several meanings, but here it means “to stay / to remain”.

ficar na cama ≈ “to stay in bed”

If you used estar:

estar na cama – “to be in bed” (just describing location/state, not the idea of staying there)

So:

Eu quero ficar na cama hoje.
→ I want to stay in bed (instead of getting up / going out).

If you said:

Eu quero estar na cama hoje.

it would sound odd or at least less natural in this context, as if you were expressing a wish to be found in bed at some point, not really the idea “I’d just like to stay in bed all day”.

In short: with the meaning “stay / remain”, ficar is the right verb.

What does na mean in na cama?

Na is a contraction of the preposition em (“in / on / at”) + the feminine singular article a (“the”):

em + a = na

So:

na cama = em + a cama = “in the bed” / “in bed”

Other examples:

no quarto = em + o quarto (“in the bedroom”)
nas férias = em + as férias (“on holiday”)

Why na cama (“in the bed”) when English just says “in bed” with no “the”?

Portuguese often uses a definite article where English omits it.

So:

English: in bed
Portuguese: na cama (literally “in the bed”)

This is normal and very natural. Some patterns:

Estou na cama. – “I’m in bed.”
Vou para a cama. – “I’m going to bed.”

You would only drop the article in special structures or fixed expressions, e.g.:

Estou de cama. (idiom, “I’m bedridden / stuck in bed (ill)”)
em cama de hospital – “in a hospital bed”

But for your sentence, na cama is exactly what you should use.

What is the difference between na cama and à cama?

These are two different contractions:

na = em + a (“in/on the”) → location
à = a + a (“to the”) → direction

So:

ficar na cama – “to stay in bed” (you’re already there; you remain there)
ir para a cama / ir à cama – “to go to bed” (you’re going towards the bed)

In modern European Portuguese, ir para a cama is more common in everyday speech:

Vou para a cama. – “I’m going to bed.”

But for your sentence, you’re talking about staying in bed, so na cama (with ficar) is the correct choice.

Can hoje go in a different position? For example, Hoje quero ficar na cama?

Yes. In Portuguese, adverbs like hoje (“today”) are quite flexible. All of these are correct:

Eu quero ficar na cama hoje.
Quero ficar na cama hoje.
Hoje quero ficar na cama.
Hoje eu quero ficar na cama.

The differences are mostly about emphasis:

Starting with Hoje puts more focus on today:
Hoje quero ficar na cama. – “Today, I want to stay in bed.”
Keeping hoje at the end is very neutral and common in speech:
Quero ficar na cama hoje.

What you would normally avoid is splitting things in clumsy ways like:

✗ Eu quero hoje ficar na cama. – technically possible but sounds a bit stiff / bookish in everyday speech.

Is Eu quero ficar na cama hoje what a European Portuguese speaker would naturally say?

Yes, it’s perfectly natural and correct in European Portuguese.

You will also hear other very common (often more idiomatic) ways to express exactly this idea, for example:

Hoje só me apetece ficar na cama.
“Today I just feel like staying in bed.”
Hoje apetecia-me ficar na cama.
“Today I’d (really) feel like staying in bed.”
Hoje queria ficar na cama.
Literally “Today I wanted to stay in bed,” but often used with a soft / wishful tone, like “I wish I could stay in bed today.”

But your sentence Eu quero ficar na cama hoje (or without eu) is fully natural and easy to understand.

Why is ficar in the infinitive form and not conjugated like fico or something similar?

After querer (when it means “to want”), the next verb is used in the infinitive form:

querer + infinitive

So:

quero ficar – “I want to stay”
queres ficar – “you (sing.) want to stay”
quer ficar – “he/she/you (formal) wants to stay”
queremos ficar – “we want to stay”

If you conjugated ficar here:

✗ Eu quero fico na cama hoje. – incorrect

That would be like saying in English “I want I stay in bed today.” If you really wanted the structure “I want that I stay…”, in Portuguese you’d say:

Eu quero que eu fique na cama.
(with fique, the subjunctive form, not used in your original sentence)

But in normal speech, we use the simple querer + infinitive pattern: quero ficar.

How would this sentence change with other subjects, like “you” or “we”?

You keep ficar in the infinitive and change the form of querer (and the subject pronoun, if you include it).

Present tense of querer (European Portuguese):

eu quero – I want
tu queres – you (singular, informal) want
ele/ela quer – he/she wants
você quer – you (formal) want
nós queremos – we want
eles/elas querem – they want
vocês querem – you (plural) want

Examples with your sentence:

Tu queres ficar na cama hoje. – You (informal sing.) want to stay in bed today.
Ele quer ficar na cama hoje. – He wants to stay in bed today.
Nós queremos ficar na cama hoje. – We want to stay in bed today.
Eles querem ficar na cama hoje. – They want to stay in bed today.

In informal speech, the subject pronouns (tu, nós, etc.) are often omitted when the context is clear:

Queres ficar na cama hoje? – Do you want to stay in bed today?
Queremos ficar na cama hoje. – We want to stay in bed today.

How would I say this more politely, like “I would like to stay in bed today”?

In European Portuguese, a very natural, more polite or softer version is:

Gostava de ficar na cama hoje.

This literally uses the “imperfect” of gostar (“I used to like / I would like”) but in Portugal it’s very commonly used with the meaning “I’d like / I would like”, and it sounds gentler than Eu quero.

You can also say:

Eu gostaria de ficar na cama hoje.

This is more formal or careful, and you’ll see it a bit more in writing or polite requests, but gostava de is extremely common in everyday European Portuguese.

Compare:

Eu quero ficar na cama hoje. – more direct: “I want to stay in bed today.”
Gostava de ficar na cama hoje. – softer, more like “I’d like to stay in bed today.”