Burn the midnight oil
/bɜːn ðə ˈmɪdnaɪt ɔɪl/neutral, informalUK · US · AU · IE · CA
What does “Burn the midnight oil” mean?
Burn the midnight oil means to stay awake working or studying late into the night.
This idiom means staying awake late into the night to complete important work. It shows dedication and effort, usually when time is running out.
The phrase feels positive because it praises hard work, but it can also suggest tiredness. It is common in both casual chats and office settings.
When do people say it?
People say this when someone works late to meet a deadline or prepare for an exam.
“Maria had to burn the midnight oil to finish her essay before morning.”
Is it formal or informal?
Register: neutral, informal. It is most at home in both everyday conversation and professional writing. Most common in UK and US and AU and IE and CA.
Where does it come from?
Long ago, people used oil lamps to see in the dark at night. Working late meant using up extra lamp oil while others were asleep.
Origin confidence: Well documented
How do you say “Burn the midnight oil” in other languages?
Last reviewed 2026-09-11