Introduction to Infinitiv ohne zu

You already know that many German verbs require zu before an infinitive — Ich versuche, früh aufzustehen. But there is a specific and consistent group of verbs and constructions where zu is completely absent. Understanding which verbs belong to this group — and why — removes a large source of errors and makes your infinitive constructions immediately more natural. The rule is not arbitrary: it follows a clear grammatical logic that, once understood, applies reliably across the whole language.

Why Infinitiv ohne zu Matters

You have already been using it without knowing the rule: Every time you say Ich muss lernen or Ich kann schwimmen, you are using an infinitive without zu. Learning the full set of verbs that follow this pattern gives you conscious control over something you have been doing intuitively.
Adding zu where it should be absent is an immediate error: Ich kann zu schwimmen is ungrammatical. Knowing the rule protects you from this mistake.
The perfect tense of these verbs is irregular: When modal verbs and a small set of other verbs appear in the Perfekt alongside an infinitive, they form a double infinitive — not a past participle. This is one of the most distinctive and counterintuitive features of German grammar.
The group is larger than just modal verbs: Learners who only know "modals don't use zu" miss the perception verbs, lassen, helfen, gehen, bleiben, and lernen — all of which follow the same pattern.

Understanding Infinitiv ohne zu

The Core Rule

Certain verbs in German function as the main conjugated verb of the sentence while a second verb appears as a bare infinitive at the end — without zu. These verbs form a closed group. For all other verbs, zu is required.

Group 1 — Modal Verbs (Always without zu)

The six modal verbs always take a bare infinitive. This is the most important group:

Modal verb	Meaning	Example
können	can / to be able to	Ich kann Deutsch sprechen.
müssen	must / to have to	Du musst jetzt gehen.
wollen	to want to	Sie will ins Kino gehen.
sollen	to be supposed to	Er soll um 8 Uhr da sein.
dürfen	to be allowed to	Ihr dürft hier nicht rauchen.
mögen / möchten	to like / would like to	Ich möchte einen Kaffee trinken.

Group 2 — Perception Verbs (sehen, hören, fühlen, spüren)

Verbs of perception take a bare infinitive when they describe witnessing an ongoing action — someone seeing, hearing, or feeling something happening:

Verb	Meaning	Example
sehen	to see	Ich sehe ihn kommen. (I see him coming.)
hören	to hear	Sie hört das Kind weinen. (She hears the child crying.)
fühlen	to feel	Ich fühle mein Herz schlagen. (I feel my heart beating.)
spüren	to sense	Er spürt den Wind wehen. (He feels the wind blowing.)

Note: When the perception verb describes a completed action rather than an ongoing one, a dass-clause with a finite verb is used instead: Ich sah, dass er gegangen war.

Group 3 — lassen

Lassen always takes a bare infinitive regardless of its meaning (letting, leaving, having something done):

Meaning of lassen	Example
To let / allow	Lass mich das machen. (Let me do that.)
To have something done	Ich lasse das Auto reparieren. (I am having the car repaired.)
To leave something (somewhere)	Er lässt das Buch auf dem Tisch liegen. (He leaves the book lying on the table.)

Group 4 — Movement and Position Verbs

A small set of verbs describing movement or position take a bare infinitive when a second activity is described as happening alongside the movement:

Verb	Meaning	Example
gehen	to go (and do something)	Wir gehen heute schwimmen. (We are going swimming today.)
fahren	to go by vehicle (and do something)	Sie fährt einkaufen. (She is going shopping.)
kommen	to come (and do something)	Er kommt essen. (He is coming to eat.)
bleiben	to stay (doing something)	Sie bleibt sitzen. (She stays seated / remains sitting.)

Group 5 — lernen and helfen

Lernen and helfen can take a bare infinitive, especially in informal usage and certain fixed expressions:

Verb	Example without zu	Example with zu (also possible)
lernen	Sie lernt kochen. (She is learning to cook.)	Sie lernt zu kochen. (also correct)
helfen	Er hilft ihr tragen. (He helps her carry.)	Er hilft ihr zu tragen. (also correct)

With lernen and helfen, both forms exist. The bare infinitive is more common in spoken German; zu is more common in formal writing.

The Double Infinitive in Perfect Tense

This is the most important advanced feature of this group. When modal verbs and perception verbs appear in the Perfekt alongside a second infinitive, both verbs appear as infinitives — the modal does not become a past participle. This is called the Ersatzinfinitiv (substitute infinitive):

In present tense	In Perfekt (double infinitive)	NOT the past participle
Ich muss gehen.	Ich habe gehen müssen.	NOT: gemusst ✗
Sie kann schwimmen.	Sie hat schwimmen können.	NOT: gekonnt ✗
Er will arbeiten.	Er hat arbeiten wollen.	NOT: gewollt ✗
Ich sehe ihn kommen.	Ich habe ihn kommen sehen.	NOT: gesehen ✗
Ich lasse es reparieren.	Ich habe es reparieren lassen.	NOT: gelassen ✗

Key rule: The double infinitive only occurs when a second infinitive is present. If the modal is used alone (without a second verb), it forms a normal past participle: Das habe ich nicht gewollt. (I didn't want that.)

Word Order with Double Infinitive in Subordinate Clauses

In subordinate clauses, the double infinitive creates a specific and important word order: the conjugated auxiliary comes before the double infinitive, not after it — an exception to the normal rule:

Type	Example	Word order
Normal subordinate clause (past participle)	..., weil er gegangen ist.	auxiliary at end
Double infinitive subordinate clause	..., weil er hat gehen müssen.	auxiliary BEFORE double infinitive

Step-by-Step Guide to Infinitiv ohne zu

Is the main verb a modal? → No zu, full infinitive at the end.
Is the main verb a perception verb (sehen, hören, fühlen, spüren)? → No zu, bare infinitive describing ongoing action.
Is the main verb lassen? → No zu, regardless of meaning.
Is the main verb gehen, fahren, kommen, or bleiben followed by a second activity? → No zu.
Is this in the Perfekt with a second infinitive present? → Double infinitive: both verbs appear as infinitives; the modal or perception verb does NOT become a past participle.
Is this in a subordinate clause with a double infinitive? → The auxiliary verb comes BEFORE the double infinitive, not after.

Pro Tip: A quick test for any verb you are unsure about — if you can replace it with a modal verb (können, müssen, wollen) and the sentence still makes structural sense, it almost certainly takes a bare infinitive too. Perception verbs and lassen are the main additions beyond the modals.

Memory Pattern: Think of these verbs as "verb commanders" — they give an order or observation about another action and take that action bare, without dressing it up in zu. All other verbs are more polite: they ask the infinitive to come properly dressed with zu.

Key Examples

German	English	Note
Ich kann Deutsch sprechen.	I can speak German.	Modal können — bare infinitive, no zu
Du musst jetzt nach Hause gehen.	You have to go home now.	Modal müssen — bare infinitive at end
Ich sehe ihn die Straße überqueren.	I see him crossing the street.	Perception verb sehen — bare infinitive for ongoing action
Sie hört die Kinder singen.	She hears the children singing.	Perception verb hören — bare infinitive
Lass mich das erklären.	Let me explain that.	lassen — always bare infinitive
Ich lasse das Auto waschen.	I am having the car washed.	lassen — having something done; bare infinitive
Wir gehen heute Abend essen.	We are going out to eat tonight.	gehen + activity — bare infinitive, no zu
Sie bleibt stehen.	She stops / remains standing.	bleiben + position — bare infinitive, no zu
Ich habe das machen müssen.	I had to do that.	Perfekt with modal — double infinitive: machen müssen
Er hat sie singen hören.	He heard her singing.	Perfekt with perception verb — double infinitive: singen hören

Common Mistakes

Mistake 1: Ich kann zu schwimmen.
- Fix: Modal verbs never take zu. The correct form is Ich kann schwimmen. Adding zu after a modal is one of the most common intermediate errors and immediately sounds ungrammatical.
Mistake 2: Ich habe gemusst früh aufstehen.
- Fix: When a modal verb appears in the Perfekt alongside a second infinitive, both appear as infinitives — the double infinitive: Ich habe früh aufstehen müssen. The past participle gemusst is only used when no second infinitive is present: Das habe ich nicht gewollt.
Mistake 3: Ich sehe ihn zu kommen.
- Fix: Perception verbs take a bare infinitive for ongoing actions: Ich sehe ihn kommen. Zu is never used with sehen, hören, fühlen, spüren in this construction.
Mistake 4: Wir gehen heute zu schwimmen.
- Fix: Movement verbs describing a destination activity take a bare infinitive: Wir gehen heute schwimmen. The zu is not needed and sounds wrong.
Mistake 5: ..., weil er gehen müssen hat.
- Fix: In a subordinate clause with a double infinitive, the auxiliary comes BEFORE the double infinitive: ..., weil er hat gehen müssen. This is an exception to the normal rule that the conjugated verb comes last in a subordinate clause.
Nuance 1: lernen and helfen with and without zu.
- Fix: Both forms are grammatically correct for these two verbs: Sie lernt kochen and Sie lernt zu kochen are both acceptable. In everyday spoken German, the bare infinitive is more natural; in formal writing, zu is slightly preferred. Neither is an error.

Cultural Insights

gehen + infinitive in daily speech: The construction gehen + bare infinitive for leisure activities is extremely common and natural in everyday German. Schwimmen gehen, joggen gehen, tanzen gehen, einkaufen gehen — these collocations are how Germans naturally describe recreational outings. Using um zu instead (Ich gehe, um zu schwimmen) is grammatically correct but sounds overly formal and unusual for casual activity descriptions.
The Ersatzinfinitiv in formal and written German: The double infinitive construction appears constantly in literary and journalistic German: Er soll das gesagt haben, Sie hat nicht kommen können, Das hätte nicht passieren dürfen. Recognising these forms in written German is as important as being able to produce them — they are not rare edge cases but everyday features of written prose.

Practice Scenarios

Talking about abilities: Describing what you can or cannot do, e.g., Ich kann gut kochen, aber ich kann nicht singen. (I can cook well, but I cannot sing.)
- Ich kann... / Ich kann nicht... (I can... / I cannot...)
- Kannst du...? (Can you...?)
- Ich habe noch nie... können. (I have never been able to...)
Describing what you observed: Using perception verbs for things you witnessed, e.g., Ich habe ihn das Haus verlassen sehen — er hatte eine Tasche dabei. (I saw him leave the house — he had a bag with him.)
- Ich sehe / sah ihn... (I see / saw him...)
- Ich höre sie... (I hear her...)
- Ich habe ihn ... sehen. (I saw him...)
Making arrangements: Using lassen and gehen for plans, e.g., Ich lasse das Fahrrad reparieren und danach gehen wir essen. (I am having the bike repaired and after that we are going out to eat.)
- Ich lasse... reparieren / waschen / machen. (I am having... repaired / washed / done.)
- Wir gehen... essen / schwimmen / tanzen. (We are going... to eat / swim / dance.)

Follow-Up Questions

Why do modal verbs not need zu before the infinitive?
- Example Answer: Modal verbs are grammatically treated as the main verb of the sentence — they take the second position and conjugate for the subject. The infinitive that follows is the dependent verb completing the meaning. The zu construction is used when a verb takes an infinitive as a kind of object or complement, but modal verbs do not work that way — the infinitive is an integral part of the modal verb phrase.
When does the modal verb use its past participle instead of the double infinitive in Perfekt?
- Example Answer: The past participle is used when no second infinitive is present — when the modal stands alone: Das habe ich nicht gewollt (I didn't want that). The double infinitive occurs only when a second verb accompanies the modal: Ich habe das nicht machen wollen (I didn't want to do that).
What is the word order rule for double infinitives in subordinate clauses?
- Example Answer: This is an exception to the normal rule. In a subordinate clause with a double infinitive, the auxiliary verb comes before the double infinitive rather than at the very end: ..., weil er hat kommen müssen. In all other subordinate clauses, the conjugated verb comes last.

Conclusion

The infinitive without zu follows a clear group logic: modal verbs, perception verbs, lassen, and a small set of movement and position verbs all take a bare infinitive. Learning these groups as a system — rather than memorising individual verbs — means you will handle new examples correctly even when you encounter them for the first time. The double infinitive in the Perfekt is the most counterintuitive part, but once you know the rule (both verbs as infinitives, auxiliary before them in subordinate clauses), it becomes a reliable and elegant feature of the language.

Practice Makes Perfect

The exercises below test all five groups as well as the double infinitive in the Perfekt — pay special attention to the subordinate clause exercises, as the word order exception is the most commonly missed point at this level.