mert, mivel, ugyanis, ezért, tehát, and így: Forms and Core Pattern | Hungarian Grammar

Hungarian separates reason-giving expressions from result and inference expressions. Mert and mivel introduce a cause, ugyanis adds a following explanation, ezért points back to a cause and presents its consequence, tehát draws a conclusion, and így presents a result or manner. Their form and position reveal the direction in which the logic runs. The companion usage page develops their discourse meanings.

Compact system

Connector	Core relation	Typical position	Register
mert	direct reason	result, mert + cause	neutral
mivel	integrated/background cause	mivel + cause, result	neutral to formal
ugyanis	afterthought explanation	claim, ugyanis + explanation	neutral to formal
ezért	consequence “for this reason”	cause, ezért + result	neutral
tehát	inference/conclusion	premise, tehát + conclusion	neutral to formal
így	result or “in this way”	action/cause, így + result	neutral

These words do not take vowel-harmonic variants. Ezért is transparently ez + -ért “for this,” but functions as a fixed discourse adverb; így is also an ordinary manner adverb meaning “like this.”

Mert introduces a following reason

Nem megyek futni, mert nagyon fúj a szél.

I'm not going running because the wind is very strong.

The main assertion comes first and mert supplies the reason afterward. A comma marks the clause boundary. A mert-clause can stand as an answer fragment in conversation:

– Miért mész haza? – Mert elfáradtam.

– Why are you going home? – Because I'm tired.

Sentence-initial mert is therefore possible, but most naturally answers or continues prior discourse. For a self-contained cause-before-result sentence, mivel is usually smoother.

Mivel integrates a cause

Mivel egész éjjel havazott, az utak csúszósak.

Since it snowed all night, the roads are slippery.

Mivel commonly presents the cause as background for the main assertion. It can also follow the main clause:

Elhalasztottuk a kirándulást, mivel rossz időt jósoltak.

We postponed the outing because bad weather was forecast.

This order is grammatical, though mert is often more conversational for a straightforward answer to “why?” Mivel historically contains an inflected interrogative-relative form, but modern learners should treat causal mivel as one conjunction.

Ugyanis explains what has just been said

Korán lefekszem, ugyanis holnap hajnalban indulok.

I'm going to bed early, because I leave at dawn tomorrow.

Ugyanis cannot freely be moved before both clauses with the same function. It looks backward: the second clause justifies or clarifies the preceding claim. Within its clause it may follow a topic:

A tervet át kell dolgozni; a költségek ugyanis túl magasak.

The plan needs revision; the costs are too high, you see. (formal)

The semicolon is stylistic; a full stop or comma can be possible depending on clause independence. Unlike mert, ugyanis is not a natural one-word answer to Miért?

💡

Use mert to answer “why?” directly. Use ugyanis after a claim when the next clause supplies an explanatory aside or justification.

Ezért points from cause to consequence

Lemerült a telefonom, ezért nem tudtalak felhívni.

My phone ran out of power, so I couldn't call you.

The cause precedes; ezért is a demonstrative adverb inside the result clause, literally pointing back “for this reason.” It can follow a result-clause topic:

Tegnap sokáig dolgoztam, ma ezért később kezdek.

I worked late yesterday, so today I'm starting later.

Because ezért can itself be focused, word order is more flexible than with a pure clause-initial conjunction.

Hungarian subordination often pairs a demonstrative correlate with a conjunction:

Azért maradtunk bent, mert odakint vihar volt.

We stayed inside because there was a storm outside.

Here azért in the main clause anticipates the reason supplied by mert. Do not replace it mechanically with ezért: azért ... mert is the conventional correlate frame.

Tehát marks an inference

A boltban már sötét van, tehát valószínűleg bezárt.

The shop is already dark, so it has probably closed.

The darkness is evidence from which the speaker infers closure. Unlike ezért, tehát need not assert a real-world causal event; it can connect premise and conclusion in reasoning.

A szerződés mindkét félre kötelező, tehát egyoldalúan nem módosítható.

The contract binds both parties; therefore, it cannot be amended unilaterally. (formal)

In planned prose tehát can be set off parenthetically—a döntés tehát végleges—but commas are not automatic merely because English writes “therefore” between commas.

Így expresses result or manner

Előre lefoglaltuk a jegyeket, így nem kellett sorban állnunk.

We booked the tickets in advance, so we didn't have to queue.

This is a concrete resulting situation. In another context, így means “in this way”:

Tartsd lenyomva ezt a gombot; így indíthatod újra a készüléket.

Hold this button down; this is how you can restart the device.

The two readings overlap because a manner can enable a result. English “so” does not show which Hungarian meaning is intended.

💡

If the second clause is a logical conclusion, choose tehát. If it describes what happened or became possible through the preceding action, így is often better.

Order and punctuation templates

RESULT, mert CAUSE.
Mivel CAUSE, RESULT.
CLAIM, ugyanis EXPLANATION.
CAUSE, ezért RESULT.
PREMISE, tehát CONCLUSION.
ACTION/CAUSE, így RESULT OR MANNER.

All examples contain clause boundaries and therefore require punctuation. If an initial subordinate clause precedes its main clause, put the comma after the subordinate clause.

Segmentation exercise

az-ért → that-for; discourse function “for that reason.”
ez-ért → this-for; points back to the immediately relevant cause.
úgy and így form a deictic contrast: “that way” versus “this way/thus.”
In Azért sietek, mert késésben vagyok, azért is the main-clause correlate and mert introduces its causal specification.
In Késésben vagyok, ezért sietek, ezért belongs to the result clause and refers back to a preceding cause.

Common Mistakes

❌ Mert, egész délután esett, lemondtuk a pikniket.

Incorrect—the comma cannot separate mert from the causal clause it introduces.

✅ Mivel egész délután esett, lemondtuk a pikniket.

Since it rained all afternoon, we canceled the picnic.

❌ Nem mentem el, ezért beteg voltam.

Incorrect logical direction: ezért introduces a consequence, not the cause intended here.

✅ Nem mentem el, mert beteg voltam.

I didn't go because I was ill.

❌ Ugyanis holnap korán kelek, ma időben lefekszem.

Incorrect neutral ordering: explanatory ugyanis normally looks back to a preceding claim.

✅ Ma időben lefekszem, ugyanis holnap korán kelek.

I'm going to bed on time today because I'm getting up early tomorrow.

❌ Ezért zártam be az ablakot, mert hideg lett.

Incorrect as the ordinary correlate construction; ezért points back, while azért anticipates the mert-clause.

✅ Azért zártam be az ablakot, mert hideg lett.

I closed the window because it got cold.

Key Takeaways

Mert/mivel introduce causes; ezért/így introduce consequences; tehát draws conclusions.
Ugyanis supplies a backward-looking explanation after a claim.
Cause-first mivel and result-first mert are robust default orders.
Distinguish pointing-back ezért from anticipatory correlate azért in azért ..., mert ....
Punctuate every clear clause boundary, but do not import English parenthetical commas automatically.

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