You can survive a day in Germany without knowing how to say "to work," "to buy" or "to understand." You cannot get through five minutes without sein. It's "to be," and it carries your name, your nationality, your mood, the weather, the price, and the question of whether that seat is taken.
Six forms. They're irregular, they look nothing like each other, and they are worth memorising tonight — because the moment you have them, every noun and adjective you've already learned turns into a sentence.
sein in the Present
I am
ich bin
you are (informal)
du bist
he / she / it is
er / sie / es ist
we are
wir sind
you are (several people)
ihr seid
they are
sie sind
you are (polite)
Sie sind
Practice these words
ich bin
Quick notes:
- Unlike Finnish or Spanish, German never drops the pronoun. Bin müde is not a sentence; it's ich bin müde.
- Sie sind and sie sind are identical in speech. The pronouns lesson explains how to tell which one you're hearing.
- Ihr seid is the form learners forget, because it has no English equivalent. It's "you all are," said to friends.
- To ask a question, swap the first two words: du bist → bist du?, Sie sind → sind Sie? No extra word needed, nothing like English "do."
Fourteen Sentences You'll Use This Week
I am Martin.
Ich bin Martin.
I'm a developer.
Ich bin Entwickler.
I'm tired.
Ich bin müde.
I'm not sure.
Ich bin nicht sicher.
Are you ready?
Bist du bereit?
Are you Mr Müller?
Sind Sie Herr Müller?
This is my wife.
Das ist meine Frau.
Is this seat free?
Ist der Platz frei?
Where is the toilet?
Wo ist die Toilette?
It's too expensive.
Es ist zu teuer.
It's cold today.
Es ist kalt heute.
There are two of us.
Wir sind zu zweit.
That's all, thanks.
Das ist alles, danke.
Practice these words
Ich bin Martin.
Quick notes:
- Ich bin Entwickler — no article. German drops the "a" in front of jobs: ich bin Lehrer, ich bin Studentin. Adding ein isn't wrong, but it sounds like you're stressing a contrast.
- Ist der Platz frei? is the phrase for a busy café, a train seat and a beer garden bench. Learn it before anything else on this list.
- Das ist… is how you introduce anyone — a partner, a colleague, a child. It never changes for gender or number: das ist mein Mann, das sind meine Kinder.
- More situational sentences are in basic German phrases.
The Past You'll Actually Need: war
German has several ways to talk about the past, and for this verb everyone uses the simple one. War is what you'll hear and what you should say.
I was
ich war
you were (informal)
du warst
he / she / it was
er / sie / es war
we were
wir waren
you were (several people)
ihr wart
they were / you were (polite)
sie waren / Sie waren
Practice these words
ich war
Quick note: three sentences carry this a long way. Ich war nicht da (I wasn't there), Das war lecker (that was delicious), Wo warst du? (where were you?). Germans say Ich war rather than the longer ich bin gewesen in almost every everyday context.
When German Doesn't Use sein
This is where English speakers produce sentences that are grammatically fine and mean something they didn't intend.
Temperature and feelings take mir, not ich. Mir ist kalt — "to me it is cold." Say Ich bin kalt and you've described your personality as cold. Ich bin heiß is worse: it means hot in the attractive sense, and it's the mistake German colleagues quote for years. Same pattern for mir ist schlecht (I feel sick) and mir ist langweilig (I'm bored).
Hunger and thirst use haben. German says Ich habe Hunger and Ich habe Durst — "I have hunger." Ich bin hungrig exists and people understand it, but it's not what anyone says. The haben lesson covers the rest of that family.
Age uses sein, but without "years". Ich bin 30 is complete and normal. Ich bin 30 Jahre alt is also correct, just fuller. What doesn't work is the Romance-language version, ich habe 30 Jahre.
Three Mistakes to Avoid
Dropping the pronoun. If you speak Ukrainian, Russian or Spanish, your instinct is to say bin müde. German needs the ich every single time.
Using ist for "they". Sie ist is one person, sie sind is more than one. Mixing these is the first thing a German ear notices.
Adding "do" to questions. There's no German equivalent of "do you…?". "Are you coming?" is simply Kommst du? — verb first, done.