Sein vs. Werden: to be vs. to become

Sein means "to be" and describes a state or condition. Werden means "to become" and describes a change or transformation.

Sein: Describes a state, identity, or fact that is true.
Werden: Describes a change from one state to another or the process of becoming something.

Sein describes what something is, while werden describes a transition or change.

Sein = to be (state, identity, fact)
Werden = to become (change, transformation)
Example: Ich bin müde. (I am tired.) — state
Example: Ich werde müde. (I am becoming tired.) — process of change

Present Tense Example:

Pronoun	Sein (to be)	Werden (to become)
ich	ich bin müde (I am tired)	ich werde müde (I become am tired)
du	du bist müde (you are tired)	du wirst müde (you become tired)
er/sie/es	er ist müde (he is tired)	er wird müde (he becomes tired)
wir	wir sind müde (we are tired)	wir werden müde (we become tired)
ihr	ihr seid müde (you all are tired)	ihr werdet müde (you all become tired)
sie/Sie	sie sind müde (they are tired)	sie werden müde (they become tired)

Perfect Tense Example:

Pronoun	Sein (to be)	Werden (to become)
ich	ich bin müde gewesen (I have been tired)	ich bin müde geworden (I have become tired)
du	du bist müde gewesen (you have been tired)	du bist müde geworden (you have become tired)
er/sie/es	sie ist müde gewesen (she has been tired)	sie ist müde geworden (she has become tired)

Sein uses gewesen; werden uses geworden for past changes.

Sein

Describes states, facts, or identities
Example: Sie ist Lehrerin. (She is a teacher.)

Werden

Describes change, development, or future events
Example: Sie wird Lehrerin. (She is becoming a teacher.)

Imperfect Example:

Ich war müde.* (I was tired.) — state in the past
Ich wurde müde.* (I became tired.) — change that happened in the past

Future Example:

Ich werde müde sein.* (I will be tired.) — future state
Ich werde müde werden.* (I will become tired.) — process of becoming tired

Sein is also used as an auxiliary verb with certain intransitive verbs (e.g., gehen, kommen) to form the perfect tense. Werden is used to form the passive voice and in future constructions.

Beispiel: Ich bin gegangen. (I have gone.) — sein as auxiliary
Beispiel: Das Buch wird gelesen. (The book is being read.) — werden in passive
Beispiel: Ich werde morgen kommen. (I will come tomorrow.) — werden for future

Sein (to be): state, identity, fact
Werden (to become): change, transformation, future, passive
Examples:

Sein: Er ist Arzt. (He is a doctor.)
Werden: Er wird Arzt. (He is becoming a doctor.)
Werden future: Er wird Arzt werden. (He will become a doctor.)
Werden passive: Das Haus wird gebaut. (The house is being built.)

Confusing Sein and Werden can lead to misunderstandings about whether you’re describing a state or a change.
Remember: If you’re describing what something or someone is, use sein. If you’re describing what something or someone is becoming or the process of changing, use werden.

Correct: Er ist müde. (He is tired.)
Correct: Er wird müde. (He is becoming tired.)
Incorrect: Er wird müde gewesen. (He has become tired being — mixed forms)
Incorrect: Er ist müde geworden. (He has become tired — correct)

Sein: Ich bin hier. (I am here.)
Werden: Ich werde hier sein. (I will be here.)
Werden: Ich werde müde. (I am becoming tired.)
Werden: Ich werde Arzt. (I am becoming a doctor.)
Sein: Ich bin Arzt. (I am a doctor.)
Werden Passive: Das Essen wird zubereitet. (The food is being prepared.)

In summary, sein = "to be" (states, facts, identity), werden = "to become" (change, future, passive). Context decides which to use.

German

How do you say "I will become tired" in German?

How would you say "I am becoming tired" in German using 'werden'?

Why is 'Er ist müde geworden.' correct while 'Er wird müde geworden.' is incorrect?