Trabalhar vs. funcionar
While both trabalhar and funcionar can be translated as to work in English, they are used in different contexts and are not interchangeable. The key difference lies in whether the subject is a person exerting effort or an object, system, or plan operating correctly.
Trabalhar
A1The verb trabalhar means to work and is primarily used when referring to people performing a job, task, or exerting physical or mental effort. It implies labor, employment, or a deliberate action by a person or, sometimes, an animal.
Eu trabalho em um banco no centro da cidade.
(I work at a bank in the city center.)
Ela precisou trabalhar o dia inteiro no projeto da faculdade.
(She needed to work all day on her college project.)
Os cães de resgate trabalham incansavelmente após o desastre.
(The rescue dogs work tirelessly after the disaster.)
Minha mente trabalha melhor de manhã.
(My mind works better in the morning.)
O artista trabalha a argila para criar uma escultura.
(The artist works the clay to create a sculpture.)
Funcionar
A2The verb funcionar means to work in the sense of to function or to operate. It is used for machines, devices, systems, plans, or ideas to indicate that they are operating correctly or are effective.
O meu computador novo não está a funcionar bem.
(My new computer is not working well.)
O plano funcionou perfeitamente e nós conseguimos o contrato.
(The plan worked perfectly and we got the contract.)
A geladeira parou de funcionar ontem à noite.
(The refrigerator stopped working last night.)
Essa chave não funciona nesta porta.
(This key doesn't work in this door.)
A democracia só funciona com a participação de todos.
(Democracy only works with everyone's participation.)
Summary
In essence, use trabalhar when the subject is a person (or living being) engaged in labor, a job, or effort. Use funcionar when the subject is a machine, a system, or a plan that is either operating or not. A simple rule to remember is: people trabalham, but things funcionam.