Kill two birds with one stone
/kɪl tuː bɜːdz wɪð wʌn stəʊn/neutral, informalUK · US
What does “Kill two birds with one stone” mean?
Kill two birds with one stone means to achieve two aims with a single action.
The expression praises efficiency. It is common in everyday planning talk and in business conversation.
Some speakers now avoid the violent image and say "two for one" instead, but the idiom remains entirely standard.
When do people say it?
Used when planning: combining a trip, a task or a meeting.
“I'll visit the supplier while I'm in Leeds and kill two birds with one stone.”
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.
Where does it come from?
In English since the seventeenth century.
Origin confidence: Well documented
How do you say “Kill two birds with one stone” in other languages?
Related idioms
- Go the extra mile, To make an extra effort.
- Cut corners, To skimp on quality to save time or money.
Last reviewed 2026-09-11