Tudni vs Ismerni in Hungarian

In Brief

Hungarian divides English know between two main verbs. Use tudni for knowing a fact or answer and for knowing how to do something; use ismerni for being acquainted or familiar with a person, place, work, or subject. A useful first test is: if you can replace know with know that/how, choose tudni; if you mean be familiar with, choose ismerni.

Overview

English lets one verb cover I know the answer, I know how to swim, and I know Anna. Hungarian does not. It normally says Tudom a választ for knowledge of an answer, Tudok úszni for an ability, but Ismerem Annát for acquaintance with a person. Choosing the verb therefore depends on the kind of knowledge, not simply on the English word know.

This contrast becomes especially important around B1, when you begin discussing what you know, whom you know, and what you can do in more varied sentences. It also brings together two earlier parts of Hungarian grammar: the infinitive (the basic verb form, such as úszni, “to swim”) and the definite versus indefinite conjugation. Hungarian verb endings can show whether a direct object (the person or thing directly affected by the verb) is specific and definite.

The short rule is reliable, but the boundary is not always about “facts versus things.” You can know a title with tudni because the title is information, yet know a book with ismerni because you have read it or are familiar with it. Meaning decides the verb.

How It Works

The central contrast

Meaning	Hungarian pattern	Example	English
know a fact, answer, name, address, or other information	tudni + object/clause	Tudom a címet.	I know the address.
know that, where, why, when, who, etc.	tudni + clause	Tudom, hogy igaz.	I know that it is true.
know how to; have the ability to	tudni + infinitive	Tud vezetni.	He/She can drive.
know or be acquainted with a person	ismerni + person in the accusative	Ismered Dórát?	Do you know Dóra?
be familiar with a place, work, subject, or system	ismerni + object	Ismerjük ezt a rendszert.	We know/are familiar with this system.

The accusative is the form used for a direct object; in Hungarian it is usually marked by -t, often with linking vowels or other spelling changes. Thus Péter becomes Pétert, város becomes várost, and ő (“he/she”) becomes őt.

Tudni for information

Use tudni when the thing known can be treated as an item of information:

• Tudom a választ. — I know the answer.
• Nem tudjuk a pontos időt. — We do not know the exact time.
• Tudod a telefonszámát? — Do you know his/her phone number?

It also introduces a subordinate clause (a smaller sentence inside a larger one), often beginning with hogy (“that”) or an interrogative word such as hol (“where”), miért (“why”), or mikor (“when”):

• Tudom, hogy fáradt vagy. — I know that you are tired.
• Nem tudom, hol lakik. — I do not know where he/she lives.
• Tudjátok, mikor indul a vonat? — Do you know when the train leaves?

In careful writing, a comma separates the main clause from the subordinate clause: Tudom, hogy…

Tudni for skills and practical possibility

With an infinitive, tudni expresses learned ability or practical capacity:

• Tudok úszni. — I can swim / I know how to swim.
• Már tud olvasni. — He/She can already read.
• Nem tudom kinyitni az ajtót. — I cannot open the door.

In this construction, tudni carries the person ending, while the other verb stays in the infinitive. Compare tudok (“I can”) + úszni (“to swim”). English can also covers permission, but Hungarian tudni usually concerns ability, feasibility, or practical availability. Permission is more directly expressed with szabad: Szabad itt parkolni? means “May one park here?”

In everyday invitations, Tudsz holnap jönni? can naturally mean “Can you come tomorrow?” Here the question includes practical availability, not just physical ability.

Ismerni for familiarity and acquaintance

Use ismerni when someone or something is familiar through contact, experience, study, reading, or recognition:

• Ismerem a szomszédot. — I know the neighbour.
• Jól ismeri Budapestet. — He/She knows Budapest well.
• Ismered ezt a filmet? — Do you know this film? / Are you familiar with this film?
• Nem ismerjük ezt a módszert. — We are not familiar with this method.

Unlike tudni + infinitive, ismerni normally takes a noun or pronoun as its object. The object answers “whom?” or “what?”

Present-tense conjugation

Both verbs use the indefinite conjugation when there is no direct object or when the object is indefinite, such as egy embert (“a person”). They use the definite conjugation with a definite object, such as a választ (“the answer”), a proper name, or ezt (“this”). The subject pronoun is usually omitted because the ending identifies the subject.

Indefinite conjugation

Person	tudni	ismerni
én (I)	tudok	ismerek
te (you, singular informal)	tudsz	ismersz
ő (he/she)	tud	ismer
mi (we)	tudunk	ismerünk
ti (you, plural informal)	tudtok	ismertek
ők (they)	tudnak	ismernek

With an infinitive and no direct object of tudni, the indefinite forms are used: Tudok főzni (“I can cook”). An indefinite object also selects them: Ismerek egy jó orvost (“I know a good doctor”).

Definite conjugation

Person	tudni	ismerni
én (I)	tudom	ismerem
te (you, singular informal)	tudod	ismered
ő (he/she)	tudja	ismeri
mi (we)	tudjuk	ismerjük
ti (you, plural informal)	tudjátok	ismeritek
ők (they)	tudják	ismerik

These forms occur with definite objects: Tudom a választ, Ismered Pétert, Ismerik a várost. A following hogy-clause also commonly appears with the definite forms of tudni: Tudom, hogy…, Tudják, hogy…

The same noun can allow either verb

The choice can change the meaning even when the object remains the same:

Hungarian	Natural interpretation
Tudom a vers címét.	I know the poem’s title as a fact.
Ismerem a verset.	I know/am familiar with the poem.
Tudom az utat.	I know the route—what way to go.
Ismerem ezt az utat.	I am familiar with this road/route.
Tud magyarul.	He/She knows Hungarian; can speak/use it.
Ismeri a magyar nyelvet.	He/She is familiar with the Hungarian language, perhaps as a subject of study.

Examples in Context

Hungarian	English	Note
Tudom, hogy hol van.	I know where it is.	A known fact; tudni + clause.
Tudok úszni.	I can swim.	Learned ability; tudni + infinitive.
Ismerem Pétert.	I know Péter.	Acquaintance with a person.
Ismeri a várost?	Do you know the city?	Familiarity with a place; formal singular or third person.
Nem tudom a választ.	I don’t know the answer.	Information that is unknown.
Tudod, miért késik Anna?	Do you know why Anna is late?	Embedded question after tudni.
Nem tudok ma találkozni veled.	I can’t meet you today.	Practical possibility or availability.
A gyerek már tud olvasni.	The child can already read.	Acquired skill.
Ismersz egy jó fogorvost?	Do you know a good dentist?	Indefinite object, so ismersz.
Jól ismerjük ezt a környéket.	We know this neighbourhood well.	Familiarity gained through experience.
Nem ismerem őt személyesen.	I don’t know him/her personally.	No personal acquaintance.
Ismered ezt a dalt?	Do you know this song?	Familiarity with a work.
Tudsz magyarul?	Do you know/speak Hungarian?	Language competence; literally “Can you in Hungarian?”
Tudok egy jó éttermet a közelben.	I know of a good restaurant nearby.	Colloquial: a useful option comes to mind.
Ismerem azt az éttermet.	I know that restaurant.	I have experience of or familiarity with it.

Common Mistakes

Using tudni for personal acquaintance

• Wrong: Tudom Pétert.
• Right: Ismerem Pétert.
• Why: Knowing a person means being acquainted with that person, so Hungarian uses ismerni. The proper name is a definite direct object, which requires ismerem.

Using ismerni for a fact or answer

• Wrong: Ismerem, hogy hol van az állomás.
• Right: Tudom, hogy hol van az állomás.
• Why: A clause stating where something is conveys information. Use tudni, not ismerni.

Leaving out the infinitive after an ability

• Wrong: Tudok az úszás.
• Right: Tudok úszni.
• Why: For “know how to” or “can,” conjugate tudni and put the action in the infinitive: tudok + úszni.

Choosing the wrong conjugation

• Wrong: Ismerek a tanárt.
• Right: Ismerem a tanárt.
• Why: A tanárt means “the teacher” and is definite, so the verb needs the definite ending -em. By contrast, Ismerek egy tanárt (“I know a teacher”) has an indefinite object.

Translating every English can with tudni

• Wrong: Tudok itt parkolni? when asking whether parking is permitted
• Right: Szabad itt parkolni?
• Why: Tudok itt parkolni? can ask whether parking is practically possible. Szabad…? clearly asks for permission.

Usage Notes

Nem tudom (“I don’t know”) is one of the most frequent everyday uses of tudni. Nem ismerem needs an understood or stated object and means “I don’t know him/her/it” in the sense of lacking familiarity. This creates a useful conversational contrast: Nem tudom, ki ő means “I don’t know who he/she is,” while Nem ismerem őt means “I don’t know him/her personally.”

Hungarian often qualifies ismerni with jól (“well”), alaposan (“thoroughly”), or személyesen (“personally”): Jól ismerem a témát means “I know the subject well.” These adverbs make the degree or kind of familiarity explicit.

With languages, everyday Hungarian normally uses tud + language adverb: Tudok angolul (“I know/speak English”). Saying Ismerem az angol nyelvet is grammatical, but it presents English as a language system with which you are familiar; it does not as directly claim speaking ability.

The colloquial pattern Tudok egy jó helyet/orvost/éttermet means that the speaker knows of or can suggest a good place, doctor, or restaurant. Ismerek egy jó orvost instead emphasizes acquaintance or familiarity. The distinction can be subtle, and both may be natural in recommendation contexts.

Beyond the Basics / Advanced Use

The two verbs participate in several common extensions. Tud valamiről means “know about something”: Tudsz a változásról? (“Do you know about the change?”). Here -ról/-ről has the sense “about,” and the construction focuses on awareness that something exists or happened. Compare Ismered a változás okát? (“Are you familiar with the reason for the change?”), which takes a direct object.

Hungarian can distinguish knowledge from recognition through related verbs. Felismerni means “recognize” after seeing, hearing, or identifying someone or something: Felismertem a hangját (“I recognized his/her voice”). Megismerni often means “get to know,” “come to know,” or “recognize,” depending on context: Szeretném jobban megismerni a várost (“I would like to get to know the city better”). These prefixed verbs are related to ismerni but should not be treated as simple interchangeable forms.

Another useful pattern is úgy tudom: Úgy tudom, holnap zárva lesznek means “As far as I know, they will be closed tomorrow.” It presents information as the speaker’s current understanding and leaves room for correction. Tudtommal has a similar meaning, “to my knowledge,” and is somewhat more compact or formal: Tudtommal még nem döntöttek (“To my knowledge, they have not decided yet”).

Finally, tudni is not always equivalent to a confident command of a skill. Context can distinguish basic ability from successful performance: Tudok főzni says “I can cook,” while Jól tudok főzni says “I can cook well.” Likewise, ismerni can describe anything from slight recognition to deep familiarity; words such as kicsit, jól, and alaposan clarify the degree.

Practice Tips

1. Sort examples into three groups: fact/clause, ability + infinitive, and familiar person/place/thing. Say tudni, tudni, or ismerni before completing each sentence.
2. Practise definite and indefinite pairs aloud: Ismerek egy orvost — Ismerem az orvost; Tudok egy helyet — Tudom a címet. This connects meaning with the correct verb ending.
3. Build personal sentences you are likely to use: three things you can do (Tudok…), three people or places you know (Ismerem…), and three facts you do not know (Nem tudom…).

Related Concepts

• Prerequisite: Present Definite Conjugation — explains why forms such as tudom, tudod, ismerem, and ismeri change with a definite object.