The conjunction als is the 25th most common word in German. Simply put, a conjunction is a word that joins together sentences, clauses, phrases, or words. Many conjunctions have a very specific conjoining role, such as joining a dependent and independent clause. Als, on the other hand, is used to join together many different parts of speech. And in its different roles, it can take on different meanings. Let’s explore what these functions and meanings are and how to identify them.

Meaning and usage of als

(1) when, while (subordinating conjunction; used with an indicative past tense)

In this usage, als begins a dependent clause that has its own subject and verb. The verb of the als-clause is typically in the simple past tense.

Wir haben dich angerufen, als wir in Berlin ankamen.
We called you when we arrived in Berlin.

Als ich aus dem Zug ausstieg, hat es stark geregnet. 
When I got off the train, it was raining hard.

What is the difference between als, wenn, and wann? All three words can mean when. And all three can begin a dependent clause. But an als-clause with a past-tense verb refers to a situation in the past that happened once or for one continuous period.

Als ich meinen Freund besuchte, …
When I visited my friend (that one time), …

Als ich in die Schule ging, …
When I went to school (that one time), …

Als ich 10 Jahre alt war, …
When I was 10, … [a person is 10 years old only once]

A wenn-clause containing a past-tense verb refers to habitual or repeated past action. When means when or if when used with reference to present or future time. When used to begin a past-tense clause, wenn usually means whenever. The idea of habitual action is often reinforced with the word immer.

(Immer) wenn ich meinen Freund besuchte, …
Whenever (every time) I visited my friend, …

(Immer) wenn ich in die Schule ging, …  
Whenever (every time) I went to school, …

Wann, by contrast, is a question word. It is used in questions to ask about the time.

Wann beginnt die Vorlesung?
When does the lecture begin?

Wann fährst du in Urlaub?  
When do leave for your vacation?

And in indirect questions:

Weißt du, wann die Vorlesung beginnt?
Do you know when the lecture begins?

Ich bin mir noch nicht sicher, wann ich in Urlaub fahre.
I am not sure when I’m leaving on vacation.

(2) as if, as though (subordinating conjunction; used with verbs in the subjunctive); also: als ob, als wenn

When subordinating conjunctions begin a clause, the conjugated verb of the clause is normally at the end of the clause, as seen in the examples above. When als begins a clause with a verb in the subjunctive, however, the conjugated verb immediately follows the conjunction als.

Er tut, als hätte er uns nicht gesehen.  
He acts as if he didn’t see us.

Arbeite so, als würdest du das Geld nicht brauchen.
Work as though you don’t need the money.

Es sah aus, als würde es gleich regnen.
It looks as if it’s going to rain soon.

Als is equivalent in meaning in this usage to als ob and als wenn. When one of these combinations begins the subordinate clause, the clause retains standard dependent word order, i.e. the conjugated verb of the clause is at the end of the clause.

Er tut, als ob er uns nicht gesehen hätte.
He acts as if he didn’t see us.

Arbeite so, als wenn du das Geld nicht brauchen würdest.
Work as though you don’t need the money.

Es sah aus, als wenn es gleich regnen würde. 
It looks as if it’s going to rain soon.

When als (als ob, als wenn) is used to mean as if or as though, the verb in its clause should be in the subjunctive.  Subjunctive II (general subjunctive) occurs more frequently than Subjunctive I (special subjunctive), as in the above examples. You may hear the Indicative in these clauses in spoken language, but this is considered colloquial and not appropriate in written German. The Indicative is never used in als-clauses where als is directly followed by the verb.

(3) than (comparative conjunction)

When als follows a comparative form, it is equivalent to the English comparative than. The comparative will precede als, but it might not be the word directly before it. Als also has the meaning of than following a form of the word anders/andere-. The preceding comparatives are underlined in the examples below.

Butter ist gesünder als Margarine.
Butter is healthier than margarine.

Plötzlich kamen mehr als 30 Besucher in das kleine Museum.
Suddenly, more than 30 visitors came into the museum.

Teilzeitarbeit hat für Frauen eine größere Bedeutung als für Männer.
Part-time work has a greater meaning for women than for men.

Hast du nichts Besseres zu tun als im Internet zu surfen?
Don’t you have anything better to do than surf the Internet?

Er ist anders als sein Bruder.
He is different than his brother.

The comparative may occur in the clause preceding the als-clause. When the comparative als-clause has its own subject and verb, it is a dependent clause and is separated from the main clause with a comma.

Du darfst nicht länger bleiben, als ich es dir erlaubt habe.
You may not stay longer than I have allowed.

Als is also used in this sense following negation words like kein, niemand, nichts, alles andere. These are expressed in English variably: kein (comparative) … als no … than, not a … than, niemand als nobody but, nichts als nothing but, alles andere als anything but, far from.

Es gibt kein schöneres Geschenk als dieses Buch.
There is not a lovelier gift than this book.

Sag mir nichts als die Wahrheit!
Tell me nothing but the truth!

Die Temperaturen waren alles andere als sommerlich.
The temperatures were anything but summerlike.

Finally, in spoken language, sometimes wie can be heard with comparatives in place of als. Though people say it, it is generally considered incorrect in standard usage.

Sie ist größer wie ihr Bruder.  She is taller than her brother.

(4) as (conjunction)

Als is used to integrate adverbials or attributes into a sentence. The information in the als-phrase describes or modifies something that appears previously in the sentence.  In this usage, als functions like a preposition, but without being assigned to a particular case. As a general rule, the phrase that als introduces is in the same case as the phrase it refers back to. The als-attributes and their referents are underlined.

Sie suchte sich einen Nebenjob als Telefonistin in einem Call-Center.
She looked for a second job as a telephone operator in a call center.

Ich gebe ihm als Erstem meine Manuskripte zu lesen.
I have him be the first one to read all of my manuscripts.
(I give him as the first one all of my manuscripts to read.)

Als works in the same way in the phrase gelten als to be considered (as), to be considered (to be) though the English equivalent may omit the word as.

Diese Bergwerke gelten als sehr gefährlich.
These mines are considered dangerous.

Die Sendung gilt als eine der größten Erfolge der Fernsehgeschichte.
The show is considered one of the greatest successes in television history.