Na poštu půjdu až zítra.

In Czech, jít na poštu is the normal way to say to go to the post office.

Even though the post office is a building, Czech often uses na with certain destinations that are understood more as institutions, services, events, or functional places. So you also get things like:

• jít na policii = to go to the police
• jít na úřad = to go to the office / authority office
• jít na nádraží = to go to the station

By contrast, do often emphasizes going into something as a physical interior. In some contexts do pošty might be understood, but na poštu is the standard everyday expression for going there to use the post office service.

Poštu is accusative singular.

The preposition na can take different cases, but after verbs of motion like jít when it means to / onto / toward a destination, it takes the accusative.

So:

• pošta = nominative singular
• na poštu = accusative singular

The noun pošta is feminine, and feminine nouns ending in -a often change to -u in the accusative singular:

• škola → školu
• kniha → knihu
• pošta → poštu

Because the sentence refers to the future.

• jdu = I am going / I go
• půjdu = I will go

The verb jít is irregular in the future, and its future forms are built from a different stem:

• půjdu = I will go
• půjdeš = you will go
• půjde = he/she/it will go

So Na poštu půjdu až zítra means I’ll go to the post office only tomorrow / not until tomorrow, not that the speaker is going there now.

Because jít already has its own built-in future form: půjdu.

In Czech, many imperfective verbs form the future with budu + infinitive, for example:

• budu pracovat = I will work
• budu čekat = I will wait

But some common motion verbs are irregular and do not normally use that pattern. Instead they have special future forms:

• jít → půjdu
• jet → pojedu

So budu jít is not the normal standard way to say I will go.

Here až means something like:

• not until
• only
• as late as

So the sentence is not just I’ll go to the post office tomorrow. It is specifically:

• I won’t go to the post office until tomorrow
• I’ll go to the post office only tomorrow

That adds a sense of delay, postponement, or contrast with an earlier expected time.

There is definitely extra meaning.

• Půjdu na poštu zítra. = I’ll go to the post office tomorrow.
• Na poštu půjdu až zítra. = I’ll go to the post office not until tomorrow.

So až adds the idea that tomorrow is later than expected, planned, or desired.

For example, if someone asks why you are not going today, you might answer:

• Na poštu půjdu až zítra.

Because zítra is an adverb meaning tomorrow.

Czech often uses time expressions directly as adverbs, without a preposition:

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

So you simply say:

• půjdu zítra = I’ll go tomorrow

You do not need a preposition like English on or in.

Yes, Czech word order is flexible, and different orders change the emphasis.

This sentence puts Na poštu first, which makes the destination the topic or point of contrast. It can feel like:

• As for the post office, I won’t go until tomorrow.

Other possible word orders include:

• Půjdu na poštu až zítra.
• Až zítra půjdu na poštu.

All are possible, but the focus shifts slightly:

• Na poštu půjdu až zítra. → emphasis on the post office
• Půjdu na poštu až zítra. → fairly neutral
• Až zítra půjdu na poštu. → emphasis on tomorrow / not until tomorrow

Because jít usually refers to one specific trip in one direction, while chodit is more about repeated, habitual, or general going.

• půjdu na poštu = I’ll go to the post office (one specific time)
• chodím na poštu = I go to the post office / I usually go to the post office

In this sentence the speaker means a single future action, so půjdu from jít is the right choice.

It very often sounds like a response or contrastive statement.

Because of až zítra, it often implies something like:

• not today
• later than expected
• please wait
• I’m postponing it

So in real conversation it could answer questions like:

• Kdy půjdeš na poštu? = When will you go to the post office?
• Proč nejdeš na poštu dnes? = Why aren’t you going to the post office today?

The sentence then naturally means: I’ll go to the post office only tomorrow / not until tomorrow.

A rough guide:

• půjdu ≈ POY-doo
• poštu ≈ POSH-too

A few details:

• ů in půjdu is pronounced like a long oo
• j in Czech sounds like English y
• š sounds like English sh
• stress in Czech normally falls on the first syllable, so:
  • PŮJ-du
  • POŠ-tu
  • ZÍ-tra

Not here.

The word až has several uses in Czech, but in this sentence, with a time word like zítra, it clearly means not until / only.

So až zítra is a fixed and very common way to say:

• not until tomorrow
• only tomorrow

The context and the time expression make that meaning clear.