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Grammar 1 min read Published January 2025

By vs until - what's the difference?

By = deadline. The action happens at or before that time. One moment."Please send it by Friday." - before Friday ends, it must be doneUntil = duration.

By = deadline. The action happens at or before that time. One moment.
"Please send it by Friday." - before Friday ends, it must be done

Until = duration. The action continues up to that time, then stops.
"I'll be working until Friday." - working right up to Friday, then stopping

The test

Ask yourself - is this a point in time when something finishes, or a deadline for something to happen?

"We're open until 9pm." (we stay open continuously up to 9pm) βœ“
"Please arrive by 9pm." (deadline - be here no later than 9pm) βœ“
"We're open by 9pm." βœ— - doesn't mean the same thing

Till is the same as until - informal:
"Wait till I get back." = "Wait until I get back."

By then / until then

"By then, we'll have finished." (at that future point, it'll be done)
"Until then, we keep going." (we continue up to that point)

Frequently asked

What does "By vs until - what's the difference?" mean?

By = deadline. The action happens at or before that time. One moment."Please send it by Friday." - before Friday ends, it must be doneUntil = duration.

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