Learn Hardcore Korean: bakmulgwan ipjangryoga muryoyeyo.

가 marks the subject and often presents new, focused information. It can feel like you’re identifying which fee is free: The museum admission fee is the one that’s free.
는 marks the topic and sounds more general or contrastive: As for the museum admission fee, it’s free. This is very common in announcements or signs.

So you can say:

박물관 입장료가 무료예요. (focus on what is free)
박물관 입장료는 무료예요. (as for the admission fee, it’s free)

Why is it 박물관 입장료, not 박물관의 입장료?

In Korean, when one noun modifies another (especially Sino-Korean compounds), 의 is often dropped and the nouns simply stack. 박물관 입장료 is the natural, compact way to say museum admission fee. 박물관의 입장료 is grammatically fine but sounds more formal or bookish in everyday speech.

Is 무료 an adjective? Why is it 무료예요 and not 무료해요?

무료 is a noun meaning free of charge. To make a predicate, you use the copula 이다:

무료예요 / 무료입니다 = It is free (of charge). Saying 무료해요 is incorrect because 무료 is not a descriptive verb. In casual speech you might hear fragmentary 무료요, but the standard full form is 무료예요.

What’s the difference between 무료, 공짜, and 자유?

무료: formal/neutral for free of charge (signs, announcements, polite speech).
공짜: casual/colloquial for free (can feel slangy; avoid in formal contexts).
자유: freedom/liberty, not about price. Don’t use 자유 to mean free of charge.

Could I say 입장이 무료예요 instead of 입장료가 무료예요?

People will understand 입장이 무료예요, but the natural way is to talk about the fee: 입장료가 무료예요. Other idiomatic options:

입장료가 없어요. (There is no admission fee.)
무료로 입장할 수 있어요. (You can enter for free.)

What’s the politeness difference between 무료예요, 무료입니다, and 무료야?

무료예요: polite informal (most common in everyday polite speech).
무료입니다: polite formal (announcements, writing, customer service).
무료야: casual (to close friends, younger people).

Why is it 예요 and not 이에요 after 무료?

Use 예요 after a stem ending in a vowel, and 이에요 after a consonant:

무료 ends in a vowel sound → 무료예요.
If it ended in a consonant (e.g., 값) → 값이에요.

How is the sentence pronounced naturally?

박물관 is pronounced with nasalization: roughly [방물관].
입장료 has tensification and an inserted n-sound: roughly [입짱뇨].
무료예요 stays close to spelling: roughly [무료예요]. Put together: [방물관 입짱뇨가 무료예요]. (Official romanization ignores these sound changes.)

Can I drop the particle and say 박물관 입장료 무료예요? What about on signs?

In conversation, dropping 가 is common and 박물관 입장료 무료예요 sounds fine. On signs, you’ll often see even shorter noun phrases like 입장료 무료, 관람료 무료, or 무료 입장 without any verb.

What’s the difference between 무료 and 유료?

무료: free of charge.
유료: paid/fee-based. Example contrast: 입장료는 무료지만, 주차는 유료예요. (Admission is free, but parking is paid.)

Could I make the museum the topic, like 박물관은 입장료가 무료예요?

Yes. This sets the broader topic 박물관은 (as for the museum) and then states about it that the admission fee is free (입장료가 무료예요). It’s natural if you’re contrasting this museum with others or continuing talk about the museum specifically.

How would I say “Admission is 5,000 won” using the same pattern?

박물관 입장료가 5천 원이에요. You can also make it formal: 박물관 입장료는 5천 원입니다.

What does each part mean, literally?

박물관: museum
입장료: admission fee (입장 entry/admission + 료 fee)
가: subject marker
무료: free of charge
예요: copula (polite) meaning is So: The museum admission fee + subject marker + is + free (of charge).

Are there other natural ways to express the same idea?

입장료가 없습니다. (There is no admission fee.)
무료로 입장하실 수 있습니다. (You can enter for free. – formal/polite)
입장 무료예요. (Elliptical but common in speech/signs)