Baju itu terlalu ketat, jadi saya mau tukar ukuran.

In Indonesian, demonstratives like ini and itu usually come after the noun.

• baju itu = that shirt / those clothes
• rumah ini = this house

So baju itu is the normal Indonesian word order, even though English says that shirt.

Baju can mean clothes, clothing, or a top/shirt-like garment, depending on context.

In this sentence, it most naturally means something like:

• shirt
• top
• piece of clothing

If you wanted to be more specific, Indonesian could use words like:

• kemeja = shirt
• kaus = T-shirt
• pakaian = clothing/clothes (more general)

So baju is a common everyday word, but it is not always as precise as English.

This is an important difference:

• terlalu = too, as in more than is good/comfortable/acceptable
• sangat = very

So:

• Baju itu terlalu ketat = That shirt is too tight
• Baju itu sangat ketat = That shirt is very tight

In your sentence, terlalu is used because the tightness is a problem and is the reason the speaker wants to exchange it.

Ketat often means tight, especially for clothing:

• celana ketat = tight pants
• baju ketat = tight shirt

But it can also mean strict or tight in other contexts:

• aturan ketat = strict rules
• pengamanan ketat = tight security

So the exact meaning depends on context. Here, with baju, it clearly means tight-fitting.

Here, jadi means so, therefore, or as a result.

It connects the two ideas:

• Baju itu terlalu ketat = The shirt is too tight
• jadi saya mau tukar ukuran = so I want to change the size

It works like a result/conclusion word.

Other possible translations in English:

• so
• therefore
• that’s why

Yes. Mau commonly means want to.

• saya mau = I want to
• dia mau pergi = he/she wants to go

It is very common in everyday Indonesian.
Compared with other options:

• mau = common, natural, everyday
• ingin = also want, but often feels a bit more formal or deliberate

So saya mau tukar ukuran is a natural everyday way to say I want to exchange for another size.

Yes, it is normal. Indonesian often mixes elements that are not all at exactly the same formality level.

• saya = polite/neutral I
• mau = common everyday want to

So saya mau is completely natural and widely used.

If you wanted a more formal version, you could say:

• Saya ingin menukar ukurannya.

But the original sentence still sounds fine in normal conversation.

After modal-like words such as mau, Indonesian often uses the base verb.

So:

• saya mau tukar ukuran = I want to exchange the size

This is very natural in conversation.

A more formal or fully marked version could be:

• saya mau menukar ukuran
• saya ingin menukar ukurannya

In everyday speech, Indonesian frequently uses the simpler base form after words like:

• mau
• akan
• bisa

Yes, literally it is something like exchange size, but the natural English meaning is:

• exchange it for another size
• change to a different size

Indonesian often leaves out information that is obvious from context.
Here, the speaker does not repeat the full object because it is understood: they want to exchange the clothing item for a different size.

More explicit versions could be:

• saya mau tukar ke ukuran lain
• saya mau menukarnya dengan ukuran lain

But tukar ukuran is a common, concise way to say it in everyday speech.

Not necessarily. In casual Indonesian, tukar ukuran is often acceptable because the meaning is clear.

But if you want to say it more explicitly, you can add extra words:

• tukar ke ukuran lain = change to another size
• tukar dengan ukuran lain = exchange it for another size

So the original sentence is understandable and natural in everyday use, but it is somewhat shortened.

Yes. Ukuran can mean:

• size
• measurement
• dimensions

The exact meaning depends on context.

With clothing, ukuran usually means size:

• ukuran kecil = small size
• ukuran besar = large size

So in this sentence, ukuran clearly means size.

Both can work, but they feel slightly different.

• ukuran = size, in a general sense
• ukurannya = the size / its size

The original sentence uses the simpler form ukuran, which is common in speech.

A more explicit version could be:

• Baju itu terlalu ketat, jadi saya mau tukar ukurannya.

That makes the reference a little clearer: the size of that shirt.

In conversation, though, Indonesian often leaves off -nya when the meaning is already obvious.

Yes, it is understandable and fairly natural, especially in everyday speech.

The original:

• Baju itu terlalu ketat, jadi saya mau tukar ukuran.

Some slightly more explicit or polished alternatives are:

• Baju itu terlalu ketat, jadi saya mau tukar ke ukuran lain.
• Baju itu terlalu ketat, jadi saya ingin menukarnya dengan ukuran lain.
• Baju itu terlalu ketat, jadi saya mau ganti ukuran.

So the original is fine, but Indonesian offers several ways to say the same idea depending on how casual or explicit you want to be.