Splatnost je zítra.

• splatnost = the subject of the sentence
• je = the verb, specifically 3rd person singular of být (to be)
• zítra = an adverb of time (tomorrow)

So the structure is basically:

• subject + to be + time expression

This is very similar to English sentences like The meeting is tomorrow.

Je is the present-tense form of být (to be) for he/she/it or any singular noun.

Since splatnost is a singular noun, Czech uses je:

• splatnost je = the due date is

In Czech, you normally do not drop the verb to be in this kind of sentence. So Splatnost zítra would sound incomplete.

This is normal in both Czech and English.

Czech often uses the present tense of být when stating a scheduled or fixed fact about the future:

• Schůzka je zítra. = The meeting is tomorrow.
• Zkouška je v pátek. = The exam is on Friday.

So Splatnost je zítra is completely natural. It means that the due date falls on tomorrow.

It is in the nominative singular, because it is the subject of the sentence.

A good basic rule is:

• the thing that is something, or the thing being talked about as the subject, is usually in the nominative

Here, splatnost is the thing being described, so nominative is expected.

Splatnost is feminine.

Many Czech nouns ending in -ost are feminine abstract nouns, for example:

• radost = joy
• možnost = possibility
• povinnost = duty
• splatnost = due date / due time / maturity

Even though it ends in a consonant sound, it still belongs to a feminine noun pattern.

No. Zítra is an adverb, not a noun.

That is why it does not need a preposition and does not change form here. It simply answers the question when?

• Kdy? = When?
• Zítra. = Tomorrow.

So you do not analyze zítra here as a case form of a noun. It is just a time adverb.

Because Czech often uses bare time adverbs without a preposition where English may or may not use one.

Compare:

• zítra = tomorrow
• dnes = today
• včera = yesterday

You simply say:

• Je to zítra.
• Splatnost je zítra.

No extra preposition is needed.

Czech has no articles. There is no direct equivalent of a or the used the way English uses them.

So splatnost can mean something like:

• the due date
• due date
• the payment due date

The exact interpretation comes from context.

This is one of the biggest differences from English.

Yes, Czech word order is fairly flexible.

Splatnost je zítra is a natural, neutral sentence if you are talking about the due date and then saying when it is.

You could also hear:

• Zítra je splatnost.

But that usually shifts the emphasis more toward zítra.

A simple way to think about it:

• Splatnost je zítra. = neutral, common
• Zítra je splatnost. = more emphasis on tomorrow

Both are understandable, but the first version is the safer default.

Normally, no.

In Czech, the verb být in the present tense is often omitted only in some special styles, such as headings, notes, or very compressed expressions. In a normal full sentence like this, je should stay:

• Splatnost je zítra. ✓
• Splatnost zítra. ✗ as a normal sentence

So for standard spoken and written Czech, keep je.

A simple pronunciation guide:

• splatnost ≈ SPLAHT-nost
• je ≈ ye
• zítra ≈ ZEE-tra

A few useful points:

• Czech stress is usually on the first syllable of each word.
• j in Czech sounds like English y in yes.
• í is a long vowel, so zítra has a long ee sound.

So the whole sentence sounds roughly like:

SPLAHT-nost ye ZEE-tra

It sounds fairly neutral to formal, and it fits especially well in business, billing, banking, or administrative contexts.

Because splatnost is a specific term, the sentence feels more like something you might see in:

• an invoice
• a payment reminder
• a financial message
• office communication

In everyday casual speech, people might sometimes phrase things differently depending on the exact context, but Splatnost je zítra is perfectly natural Czech.