what is it?
The zu-infinitive is a construction in which the particle zu is placed directly before an infinitive verb to form a dependent infinitive clause. It works similarly to the English «to + verb» pattern (e.g. «to call», «to practise») and is triggered by certain verbs, nouns, and adjectives in the main clause. The infinitive itself does not change form; only zu is added. The zu-infinitive clause normally follows the main clause and is separated from it by a comma.
when to use it
Use the zu-infinitive after the following trigger types:
Verbs such as versuchen (to try), vergessen (to forget), anfangen (to start), aufhören (to stop), planen (to plan), and vorhaben (to intend).
Nouns such as Lust (desire/feel like), Zeit (time), and Angst (fear). These nouns appear in the main clause and the zu-infinitive clause expresses what the noun refers to.
Adjectives in es ist + adjective constructions, such as wichtig (important), schwierig (difficult), schön (nice), and einfach (easy).
brauchen + nur/nicht: The verb brauchen used with nicht or nur also takes a zu-infinitive: Du brauchst nicht zu kommen.
No zu after modal verbs or certain other verbs. Modal verbs (müssen, können, dürfen, sollen, wollen, mögen) and the verbs gehen, sehen, hören, lassen take a bare infinitive — never zu.
formation
For most verbs, place zu directly before the infinitive. For separable verbs, insert zu between the prefix and the verb stem — the result is written as one word.
| verb type | infinitive | zu-infinitive form |
|---|---|---|
| non-separable | arbeiten | zu arbeiten |
| non-separable | üben | zu üben |
| non-separable | kommen | zu kommen |
| separable | anrufen | anzurufen |
| separable | aufhören | aufzuhören |
| separable | einkaufen | einzukaufen |
The zu-infinitive clause is placed after the main clause and separated by a comma. Any objects or adverbs belonging to the infinitive clause come before zu + infinitive at the end of the clause.
Word order inside the zu-infinitive clause: [other elements] + [zu + infinitive]. Example: Ich habe vergessen, dich anzurufen. — «dich» (the object) comes before «anzurufen».
examples in context
common pitfalls
Placing zu before a separable verb instead of inside it.
With separable verbs, zu goes between the prefix and the stem — not before the whole word.
✗ Ich habe vergessen, zu anrufen.
✓ Ich habe vergessen, anzurufen.
Adding zu after a modal verb.
Modal verbs (müssen, können, wollen, etc.) always take a bare infinitive. Adding zu is a direct interference from English.
✗ Ich muss zu arbeiten.
✓ Ich muss arbeiten.
Using an English-style gerund (-ing form) instead of the zu-infinitive.
German has no gerund. Where English uses a verb ending in «-ing» as a noun or complement (e.g. «I feel like swimming»), German uses zu + infinitive.
✗ Ich habe Lust schwimmend.
✓ Ich habe Lust, zu schwimmen.
Three sentences, graded here. Nothing is saved and no account is needed.
Morgen früh müssen wir den Zug um sechs Uhr ___. (nehmen)
Fill in the blank with the correct form of the verb in parentheses.