La validité expire demain.

In French, a noun used as the subject of a sentence usually needs an article. So la validité is the normal way to say the validity.

English often drops articles in places where French keeps them. Compare:

• La validité expire demain.
• The validity expires tomorrow.

Without la, the sentence would sound incomplete in standard French.

Validité is a noun meaning validity or period of validity.

In this kind of sentence, it often refers to how long something remains valid, such as:

• a ticket
• a passport
• a contract
• an offer
• a card

So la validité expire demain is a formal way to say that the item’s valid period ends tomorrow.

Because expire is the present tense of the verb expirer: to expire.

So:

• La validité expire demain = the validity expires tomorrow

If you said est expirée, that would mean has expired / is expired, which describes a state rather than an action happening tomorrow.

Compare:

• La validité expire demain. = It expires tomorrow.
• La validité est expirée. = It has expired / it is expired.

So the sentence uses expire because it is talking about a future event from the point of view of the present.

French often uses the present tense for near-future events, just like English can.

Compare in English:

• The offer ends tomorrow.
• My train leaves at 8.

French does the same:

• La validité expire demain.

You could also make the future more explicit with the simple future:

• La validité expirera demain.

Both are correct, but the present tense is very natural here.

Mostly, yes in this context, but you should be careful.

In French, expirer can mean:

• for something to run out or expire
• in some contexts, to breathe out
• in older or formal language, to die

In everyday administrative or practical French, expirer is commonly used for dates, permits, subscriptions, documents, and offers.

Examples:

• Mon passeport expire en juin.
• Cette carte expire demain.

So in this sentence, it is a normal formal/practical use.

That is the most natural placement here. French often puts time expressions like demain after the verb.

So:

• La validité expire demain.

is the standard order.

You can move demain for emphasis, but that is less neutral:

• Demain, la validité expire.

That version sounds more marked, as if tomorrow is being emphasized.

No. Demain is used directly, without a preposition.

So you say:

• demain = tomorrow

Not:

• à demain in this sentence

Be careful: À demain ! does exist, but that means See you tomorrow! It is a fixed expression, not the same grammar as here.

Because validité is a feminine noun, so it takes la.

Many French nouns ending in -ité are feminine, for example:

• la possibilité
• la liberté
• la sécurité
• la validité

This is a very useful pattern, though, as always in French, it is best learned with the article: la validité, not just validité.

Yes, especially in formal, administrative, technical, or business contexts.

It sounds natural for things like:

• a document
• a coupon
• an offer
• a subscription
• a card
• a warranty

In very everyday speech, people might also say something more concrete, depending on the object:

• La carte expire demain.
• L’abonnement se termine demain.
• Le passeport n’est plus valable à partir de demain.

So your sentence is correct and natural, but it has a slightly formal or official tone.

Usually no, because validation and validité do not mean the same thing.

• validité = validity, the state or period of being valid
• validation = validation, approval, confirmation, the act of validating

So if you are talking about how long something remains valid, validité is the right word.

Very often, French speakers mention the item itself rather than la validité.

For example:

• Mon passeport expire demain.
• Le billet expire demain.
• L’offre expire demain.

Using la validité is common when the focus is specifically on the validity period rather than on the object itself. That is why it often appears in formal notices or official wording.