Ovaj kalup je manji od onoga koji obično koristim.

Kalup is a masculine noun. Its basic meaning is mold or form, but in real-life contexts it can also mean things like a baking tin, cake pan, or another kind of shaped container/tool.

So the exact English word depends on context:

• baking: tin / pan
• crafts or manufacturing: mold
• general shaping tool: form

Grammatically, though, it behaves as a regular masculine noun here.

Because kalup is masculine singular, and ovaj has to agree with it.

Croatian demonstratives change for gender, number, and case:

• ovaj = masculine singular
• ova = feminine singular
• ovo = neuter singular

Since the subject is ovaj kalup, both words are in the nominative singular masculine.

Mali means small, while manji means smaller.

This sentence is making a comparison, so Croatian uses the comparative form:

• mali = small
• manji = smaller

This is an irregular-looking comparative, so it is worth memorizing. Also, manji agrees with kalup, so it is in the masculine singular form.

Je is the 3rd person singular present of biti (to be).

The structure is:

• Ovaj kalup = subject
• je manji = is smaller

So this is a standard Croatian to be + adjective/comparative sentence.

In Croatian, one very common way to express comparison after a comparative adjective is:

comparative + od + genitive

So:

• manji od... = smaller than...
• veći od... = bigger than...
• bolji od... = better than...

That is exactly what is happening here:

• manji od onoga = smaller than that one

Because od requires the genitive case in this kind of comparison.

The base pronoun is onaj (that one), but after od it changes to the genitive form:

• nominative: onaj
• genitive: onoga

So:

• od onoga = than that one

This is one of the most important things to notice in the sentence: after od, you do not keep the nominative form.

Yes, in a sense the noun is omitted because it is understood from context.

Onoga means that one, and it stands in place of something like:

• od onoga kalupa = than that mold/pan

Croatian often leaves out a repeated noun when it is obvious. So instead of repeating kalup, the sentence simply uses the pronoun.

This is very natural and common.

Because koji refers to kalup / onaj kalup, which is masculine singular inanimate, and inside the relative clause it functions as the direct object of koristim.

For masculine singular:

• animate accusative often looks like genitive: kojega
• inanimate accusative is the same as nominative: koji

Since kalup is inanimate, the correct form here is:

• koji obično koristim

In other words, it means:

• the one that I usually use

not

• the one whom I usually use, which would be animate and would require a different pattern.

Because koji already plays the role of the object inside the relative clause.

The clause is:

• koji obično koristim

Literally, the relative pronoun is the thing being used. So adding ga would be unnecessary and ungrammatical in standard Croatian here.

Compare the logic:

• koristim kalup = I use the mold
• kalup koji koristim = the mold that I use

The relative pronoun already carries the object function.

Koristim is:

• 1st person singular
• present tense
• from the verb koristiti = to use

So it means:

• I use
• or in this context, I usually use

The subject I is not stated because Croatian usually leaves subject pronouns out when the verb ending already makes the person clear.

Obično means usually. It is an adverb.

Here it modifies koristim:

• koji obično koristim = which I usually use

Its position is natural and common, but Croatian word order is fairly flexible. You may also hear variants like:

• koji koristim obično

However, koji obično koristim sounds more neutral and standard.

Yes, to some extent. Croatian word order is more flexible than English word order, especially when the meaning is already clear from endings and context.

For example, you could also hear:

• Ovaj je kalup manji od onoga koji obično koristim.

That still means the same thing. The difference is mostly in emphasis and rhythm.

But some parts should stay together logically:

• manji od onoga belongs together as the comparison
• koji obično koristim belongs together as the relative clause

So the order is flexible, but not random.

They are both demonstratives, but they point to different things:

• ovaj = this (closer to the speaker)
• onaj = that / that one over there (farther away, or more clearly distinct)

So the sentence contrasts:

• ovaj kalup = this mold/pan
• onoga = that one

Croatian also has taj, which often means that in a more neutral or intermediate sense. English learners often notice that Croatian has a more detailed demonstrative system than English.

Sometimes yes, but od is the most straightforward choice here.

With comparative adjectives, Croatian commonly uses:

• manji od onoga...

You can also sometimes hear nego, especially when what follows is more clause-like:

• manji nego što sam mislio
• smaller than I thought

In your sentence, because the comparison is directly with that one, od onoga koji obično koristim is the most natural and standard structure.