
kontrollieren
to check
To check or inspect something in order to make sure that it is correct, complete, or safe.
Der Schaffner kontrolliert im Zug die Fahrkarten.
The conductor checks the tickets on the train.
to check / control
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to check
To check or inspect something in order to make sure that it is correct, complete, or safe.
Der Schaffner kontrolliert im Zug die Fahrkarten.
The conductor checks the tickets on the train.

to control
To exercise power or authority over someone or something; to dominate or direct something or someone.
Die Regierung versucht, die Ausbreitung des Virus zu kontrollieren.
The government is trying to control the spread of the virus.

to control oneself
To control one's own feelings, impulses, or behavior and not lose composure.
Obwohl er sehr wütend war, konnte er sich gerade noch kontrollieren und blieb ruhig.
Although he was very angry, he was just able to control himself and stayed calm.
'Kontrollieren' means 'überprüfen' (to check) or 'beherrschen' (to control), but not 'to operate a device'. Although it resembles the English 'to control', German uses the verb 'steuern' (to steer/control) for operating a vehicle or device.
Der Pilot steuert das Flugzeug sicher durch den Sturm.
The pilot steers the plane safely through the storm.
The verb 'kontrollieren' almost always requires a direct object in the accusative. You always check or control 'etwas' (something) or 'jemanden' (someone).
Die Polizei kontrolliert die Geschwindigkeit auf der Autobahn.
The police are checking speeds on the highway.
You can recognize the meaning from the context: If it is about rules, documents, or quality, it means 'überprüfen' (to check). If it is about power, influence, or a situation, it means 'beherrschen' (to control/dominate).
Der Lehrer kontrolliert die Hausaufgaben. (überprüfen)
The teacher checks the homework. (to check)
In the meaning 'überprüfen' (to check), 'kontrollieren' is often connected with documents or processes. Typical phrases are: 'die Rechnungen kontrollieren' (to check the invoices), 'die Qualität kontrollieren' (to check quality), or 'den Ölstand kontrollieren' (to check the oil level).
Bevor wir losfahren, müssen wir den Reifendruck kontrollieren.
Before we set off, we have to check the tire pressure.
The phrase 'sich kontrollieren' is reflexive and means to control one's own emotions or reactions. The reflexive pronoun 'sich' is in the accusative here.
Atme tief durch und versuche, dich zu kontrollieren.
Take a deep breath and try to control yourself.
to check / test
Prüfen and kontrollieren can both determine whether something is in order. Prüfen tends to emphasize a targeted assessment based on specific criteria. Kontrollieren more often emphasizes supervision or determining whether rules have been followed and whether everything is complete or safe.

Die Prüferin kontrolliert, ob die vorgeschriebene Ausrüstung vollständig im Bus liegt.
The inspector checks whether all the required equipment is in the bus.
Die Mechanikerin prüft nach festen Kriterien, ob die Bremsen des Busses sicher funktionieren.
The mechanic checks whether the bus brakes are working safely according to set criteria.