Learn Hardcore Spanish (Latin America): Quiero convertir mi habitación en un lugar tranquilo. - I want to turn my room into a quiet place.

Quiero convertir mi habitación en un lugar tranquilo.
Emphasizes the process/action of changing the room. You’re going to do things to it: redecorate, soundproof it, etc.
Quiero que mi habitación sea un lugar tranquilo.
Emphasizes the desired state/result (that the room be peaceful), without highlighting the process.

Grammatically:

querer + infinitive (quiero convertir) = “I want to do X.”
querer que + subjunctive (quiero que… sea) = “I want (something) to be/do X.”

So your sentence is perfectly natural if you want to highlight the act of transforming the room.

You could also say:

Quiero transformar mi habitación en un lugar tranquilo. (very similar idea)

How does convertir en work? Do I always need en after convertir in this meaning?

When convertir means “to turn/transform (something) into (something)”, you normally use convertir + direct object + en + result:

convertir mi habitación en un lugar tranquilo
= turn my room into a peaceful place

Structure:

convertir algo en algo
convert something into something

So:

Quiero convertir esta oficina en una sala de reuniones.
El proyecto convirtió el barrio en una zona muy cara.

Without en, convertir often sounds incomplete or shifts toward meanings like “to convert (someone) [religiously]”:

Convertir a alguien al cristianismo.

So for “turn X into Y”, yes, en is normally needed.

What’s the difference between convertir and convertirse en?

They’re closely related, but:

convertir (non‑reflexive) focuses on the agent doing the transforming:
- Quiero convertir mi habitación en un lugar tranquilo.
  I (the subject) am going to transform it.
convertirse en (reflexive) focuses on the thing that undergoes the change:
- Mi habitación se va a convertir en un lugar tranquilo.
  My room is going to become a peaceful place.

Patterns:

convertir algo en algo = to turn something into something
algo se convierte en algo = something becomes / turns into something

Both are common and correct; choice depends on whether you want to highlight the doer (I want to convert…) or the change of state (the room is going to become…).

Why is it un lugar tranquilo and not una lugar tranquila, since habitación is feminine?

The adjective tranquilo is not describing habitación; it’s describing lugar.

habitación = feminine noun
lugar = masculine noun

In Spanish, adjectives agree with the noun they modify, not with some other noun in the sentence.

So:

un lugar tranquilo
- un (masculine, singular)
- lugar (masculine, singular)
- tranquilo (masculine, singular)

If you made habitación the noun with the adjective, you would say:

Quiero que mi habitación sea tranquila.
(habitación is feminine, so tranquila is feminine.)

Why is habitación used here? In Latin America wouldn’t people say cuarto or something else?

Yes, in much of Latin America, everyday speech tends to prefer cuarto (or other regional words) over habitación:

cuarto – very common in Latin America for “room” (especially bedroom)
recámara – Mexico and some other areas, “bedroom”
pieza – some countries in the Southern Cone (Chile, Argentina, etc.)

habitación:

Is widely understood everywhere.
Sounds a bit more formal or neutral/standard, and is common in:
- Hotels (e.g., habitación doble = double room)
- More careful or written language

In everyday Latin American speech, many people would naturally say:

Quiero convertir mi cuarto en un lugar tranquilo.
Quiero convertir mi recámara en un lugar tranquilo. (Mexico, etc.)

Can I say Quiero convertir mi cuarto en un lugar tranquilo instead? Does that sound natural?

Yes, that’s very natural in Latin America.

Quiero convertir mi cuarto en un lugar tranquilo.

This version may actually sound more colloquial and typical than mi habitación in many Latin American countries. The grammar and structure stay exactly the same; you’ve only swapped one noun for another.

Could I drop mi and say Quiero convertir la habitación en un lugar tranquilo? What changes?

You can say it, but the meaning shifts a bit:

mi habitación = clearly my room (personal possession)
la habitación = the room (more generic or context‑specific)

Quiero convertir la habitación en un lugar tranquilo might be used when:

There is an obvious specific room you’re talking about (e.g., in a small apartment, or in a hotel or office).
The possession (“mine”) is already clear from context, or not important.

But if you mean “my own room” in a personal sense, mi habitación/mi cuarto is more natural.

Do I need to say yo: Yo quiero convertir mi habitación…?

No, you don’t need yo. In Spanish, the verb ending (-o in quiero) already shows the subject is I.

Quiero convertir mi habitación en un lugar tranquilo.
is fully correct and usually preferred in neutral speech.

You would add yo for:

Emphasis:
Yo quiero convertir mi habitación… (I, as opposed to someone else)
Contrast:
Yo quiero convertir mi habitación, pero mi hermano no quiere.

Otherwise, it’s more natural to omit yo.

Is tranquilo closer to “quiet” or to “calm”? Are there other adjectives I could use?

Tranquilo can mean both “quiet” and “calm/peaceful”, depending on context. In this sentence, it suggests:

Not noisy
Relaxing, peaceful, stress‑free

Other options (each with a slightly different nuance):

silencioso – very focused on silence, lack of noise
- un lugar silencioso = a silent/very quiet place
relajante – relaxing, helps you unwind
- un lugar relajante
cómodo – comfortable
- un lugar cómodo y tranquilo
acogedor – cozy, welcoming
- un lugar acogedor

You can also combine:

un lugar tranquilo y silencioso
un lugar tranquilo y acogedor

Can I change the word order and say en un tranquilo lugar? Does that sound natural?

It’s grammatically correct, but not the most natural in everyday speech.

un lugar tranquilo is the normal, neutral order.
un tranquilo lugar puts the adjective before the noun, which can:
- Sound literary or poetic, or
- Add a subtle emotional/subjective tone.

So:

For everyday speech:
Quiero convertir mi habitación en un lugar tranquilo.
In something more poetic:
Quiero convertir mi habitación en un tranquilo lugar de descanso.

In normal conversation, keep un lugar tranquilo.

How would I say this in other tenses, like past or future?

You mainly change quiero; convertir, mi habitación, en un lugar tranquilo stay the same.

Past (I wanted) – imperfect (ongoing desire in the past):
- Quería convertir mi habitación en un lugar tranquilo.
Past (I decided/attempted at some point) – preterite:
- Quise convertir mi habitación en un lugar tranquilo.
  (Implies a more specific moment: I tried or had the intention at some point.)
Future (I will want):
- Querré convertir mi habitación en un lugar tranquilo.
  (Grammatically fine, but in practice people often use a periphrasis:
  Voy a querer convertir… or just switch perspective.)

More natural to talk about plans:

Voy a convertir mi habitación en un lugar tranquilo. = I’m going to turn…
Quiero convertir… already often implies a future plan.

Is convertir mainly for religious “converting,” or can it be used for normal changes like this?

Convertir is very commonly used for ordinary transformations, not just religious ones. For example:

Convertir un garaje en un estudio.
Convertir una fábrica en un museo.
Convertir residuos en energía.

For religious use, you usually add a plus the religion:

Convertir a alguien al cristianismo / al islam / al budismo.

In your sentence, convertir mi habitación en un lugar tranquilo is a completely normal, everyday use and doesn’t sound religious at all.

Could I say Hacer de mi habitación un lugar tranquilo instead of convertir? Is there a difference?

Yes, this is another very natural option:

Quiero hacer de mi habitación un lugar tranquilo.

Structure:

hacer de [algo] [otro algo]
= to make [something] into [something else]

Nuance:

convertir… en… and hacer de… un… are very close in meaning here.
hacer de can sound a bit more idiomatic or stylistic, sometimes slightly more elevated, but it’s common in everyday speech too.

Examples:

Hicieron de la vieja casa un restaurante.
Quiero hacer de este espacio un lugar especial.

So your original:

Quiero convertir mi habitación en un lugar tranquilo.
and:
Quiero hacer de mi habitación un lugar tranquilo.

are both excellent, natural ways to say this.