Build up means to accumulate or increase (by itself) or to gradually develop and strengthen something (through your own effort). In the first case, it's something nobody collects on purpose: traffic builds up, stress builds up. In the second, you grow your strength, confidence, savings or experience: build up your confidence, build up savings.
Want to use build up in conversation?
Write a sentence — we'll show the mistakes right away and suggest how to say it more naturally.
The check is taking longer than usual. Your feedback will appear here automatically.
traffic/stress/dust + builds up; build up + strength/confidence/savings/experience; a build-up of + noun
- Traffic usually builds up near the bridge after five, so I leave work early.
- Swimming three times a week helped me build up my strength after the injury.
- Speaking English with colleagues every day slowly built up my confidence.
What changed
First versionIn five years I built up a big experience in sales.
RevisionIn five years I built up a lot of experience in sales.
In the sense of knowledge and skill, experience is uncountable, so it takes no a. A big experience would mean one striking event or impression. For plenty of skill and knowledge, say a lot of experience.
The noun has a hyphen: a build-up of traffic, a build-up of stress. The verb is two separate words: Traffic builds up. Grow up only means “become an adult”: Children grow up, problems build up.
Your turn
If you don't clean the kettle regularly, limescale will ___ inside it.
Show the answer
build up — Limescale collects in the kettle gradually, by itself: that's build up. Grow up means “become an adult” and is said about people, not limescale.
Describe a skill or quality you developed gradually. Say what you did to develop it.
I built up my confidence in English by joining a weekly speaking club at work.
Learn to use new words without mistakes
Write phrases with the words you are learning. LetsWords shows mistakes in usage and grammar, suggests corrections and explains them, and review helps the words stick.