Check what licenses the infinitive
| Introducing construction | Example |
|---|---|
| müssen / können / werden | Ich muss arbeiten. Er wird kommen. |
| lassen / sehen / hören | Ich lasse ihn reden. Ich höre ihn lachen. |
| planen / versuchen | Ich plane, früher zu kommen. |
| um … zu | Ich gehe früher los, um pünktlich anzukommen. |
| ohne … zu | Sie geht, ohne sich zu verabschieden. |
| statt … zu | Er ruft an, statt eine Nachricht zu schreiben. |
Do not add zu merely because English uses “to”: Ich kann kommen has a bare infinitive. After a verb such as planen, use a zu construction. A noun or adjective can also introduce one: der Plan, früher anzufangen; Es ist sinnvoll, vorher anzurufen.
Some verbs allow variants. Helfen and lernen are not captured by a rigid “always with/without” list; construction length and meaning matter. Brauchen occurs with and without zu, especially with negation or restriction. For a dependable learner pattern, use Du brauchst nicht zu warten. Link the whole construction to its meaning rather than transferring an English infinitive rule.
The same infinitive frame can express different relationships
- Intended goal
Ich spare, um den Kurs zu bezahlen.
The person saving intends to pay.
- Excess degree
Der Koffer ist zu schwer, um ihn allein zu tragen.
Weight prevents the action; the suitcase is not its performer.
- Sufficient degree
Der Tisch ist groß genug, um daran zu arbeiten.
Size is sufficient for a contextually understood person to work.
Who performs the infinitive action?
Nora verspricht, früher zu kommen normally means Nora will come: the main-clause subject controls the understood performer. Nora bittet Tuan, früher zu kommen means Tuan should come: the object is the performer. “The subjects must always be the same” is therefore false for infinitive complements as a whole.
For a straightforward purpose adjunct, use the same-agent pattern: Ich schreibe mit, um nichts zu vergessen. If you write so that another person understands, use an explicit subject: Ich schreibe deutlich, damit du alles verstehst. General statements can have a general performer: Es ist wichtig, Pausen zu machen. Check the intended person before choosing an infinitive instead of a finite clause.
Place zu inside the verb group
With a separable verb, put zu between prefix and stem and write one word: anrufen → anzurufen, aufstehen → aufzustehen. With an inseparable verb, keep zu separate: besuchen → zu besuchen. With a modal group: um pünktlich ankommen zu können. The modal infinitive carries zu; ankommen stays bare.
Objects, negation and adverbials precede the ending: Ich versuche, morgen nicht zu spät anzukommen. For an earlier action use a perfect infinitive when needed: Sie bedauert, die Nachricht vergessen zu haben. A passive infinitive can appear too: Er hofft, rechtzeitig abgeholt zu werden. Choose the construction’s meaning before building a longer verb chain.
Purpose, absence and replacement
Ich öffne das Fenster, um frische Luft hereinzulassen names an intention; it does not prove the intention succeeds. Sie ging, ohne die Tür zu schließen says that closing did not accompany the departure. Do not add another nicht to express that ordinary absence; it could change the logic.
Er ruft an, statt eine Nachricht zu schreiben presents calling as the alternative to writing. Anstatt is an equivalent longer form here. If a different performer must be named, use a finite construction such as ohne dass or statt dass. A finite damit clause is especially useful for a purpose with its own subject.
Not every um-zu group names a goal
Der Koffer ist zu schwer, um ihn allein zu tragen expresses excess degree: its weight prevents carrying it alone. The first zu modifies schwer; the second belongs to the infinitive. This is not someone’s purpose in making the suitcase heavy.
Der Tisch ist groß genug, um daran zu arbeiten presents sufficient size. Genug follows the adjective, whereas genug Platz puts it before a noun. The understood performer can be a contextually general person; the grammatical subject der Tisch does not do the working. This explains why a simple same-subject slogan fails for degree constructions. The finite alternative zu schwer, als dass ich ihn allein tragen könnte makes the person explicit.
Use the current punctuation distinction
An expanded sentential zu-infinitive group is separated by a comma under official § 73: Ich versuche, morgen früher anzukommen. Groups with um, ohne or statt are also separated; an inserted group needs a closing comma. Do not rely on older advice that every ordinary verb-dependent group is optional.
An unexpanded infinitive can sometimes be read as a word group or a clause: Sie versucht(,) abzunehmen. An integrated multipart predicate takes no comma: Er scheint müde zu sein; Du brauchst nicht zu warten. The distinction is structural, not a rule to place a comma before every printed zu.
Check your decisions: eight explained tasks
1. Choose: Ich kann heute kommen / zu kommen.
Ich kann heute kommen. Modal können takes a bare infinitive in this construction.
2. Form the infinitive group: Ich plane, morgen früher … (aufstehen).
Ich plane, morgen früher aufzustehen. Zu goes inside the separable verb and the expanded group is separated by a comma.
3. Who comes in Nora bittet Tuan, früher zu kommen?
Tuan. The object of bitten controls the infinitive performer; Nora is the person making the request.
4. You speak slowly so that another learner understands. Use damit.
Ich spreche langsam, damit du mich verstehst. The second performer is explicitly du; a simple same-agent purpose infinitive would not express that relation.
5. Express leaving without saying goodbye: Sie geht, …
Sie geht, ohne sich zu verabschieden. Ohne already expresses absence; no extra nicht is needed.
6. Complete “too heavy to carry alone”: Der Koffer ist __ schwer, um ihn allein __ tragen.
zu … zu. The first marks excess degree, the second the infinitive. The suitcase is not the person carrying.
7. Correct the word order: Der Tisch ist genug groß, um daran zu arbeiten.
Der Tisch ist groß genug, um daran zu arbeiten. With an adjective, genug follows it.
8. Choose the comma pattern: Er scheint(,) müde zu sein.
Er scheint müde zu sein. In this integrated multipart predicate, no separating comma is used. The printed word zu alone does not require one.
Plan a practical study afternoon
Write seven connected sentences about preparing a shared study session. Use one modal with a bare infinitive, one planned zu action, one request with an object performer, and one each with um, ohne and statt. Finish with an object that is large enough or too small for a task. Mark who performs each infinitive, check separable verbs, then check commas by structure. Read the plan as instructions a partner could actually follow.
Use the rule in a wider context
For finite purpose and result clauses, see damit and sodass. Use word-order speaking practice to keep the infinitive group together. Meaning-specific starting and finishing patterns appear in starting and ending verbs.
Questions about this topic
Must an infinitive always share the main-clause subject?
No. The understood performer can be a subject, an object or a general person, depending on the construction. Ordinary purpose clauses often follow a same-agent pattern.
Does um … zu always mean in order to?
No. After zu plus adjective or adjective plus genug, it can express a degree-related consequence or limit rather than an intended goal.
Sources and further learning
- Rat für deutsche Rechtschreibung via IDS: §73 Komma bei Nebensätzen
- IDS: Infinitiv mit oder ohne zu
- IDS: Verben mit Infinitiv ohne zu
- IDS: Satzklammer und Stellungsfelder
- IDS: Die Folgen von etwas ausdrücken
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