Did British Empire and Indonesia exist in the same era?

Yes, the two civilizations both existed around 1945 CE.

Which lasted longer, British Empire or Indonesia?

British Empire lasted longer (414 years).

British Empire: Avrupa; Indonesia: Asya

British Empire (1583 CE – 1997 CE) and Indonesia (1945 CE – present) lived in the same era.

The empire with the most extensive territory in history. It was referred to as "the empire on which the sun never sets."

Republic of Indonesia · Asia

Did British Empire and Indonesia exist in the same era?: Yes, the two civilizations both existed around 1945 CE.
Which lasted longer, British Empire or Indonesia?: British Empire lasted longer (414 years).
Which regions did British Empire and Indonesia rule?: British Empire: Avrupa; Indonesia: Asya