By Friday or until Friday? Deadlines in English

The rule

Use by for a deadline, meaning not later than: Send the report by Friday. Use until when something continues up to a time and then stops: I'm in the office until 6.

Arabic حتى and French jusqu'à are often used with deadlines, so learners say Send it until Friday. In English, one action before a deadline takes by; until needs an action or state that lasts.

Examples

In a conversation

A: Ali, could you send me the report by Friday?

B: Sure. I'm on a training course until Wednesday, so I'll send it by Thursday.

A: Perfect, thanks.

Practice

Choose the best answer. The answers are at the end of the lesson.

1. Please finish the slides ___ Thursday.
   • a) until
   • b) by
   • c) since
2. I'll be at my desk ___ 6 p.m., so call me any time.
   • a) until
   • b) by
   • c) for
3. You have ___ Friday to reply to the job offer.
   • a) by
   • b) since
   • c) until

Tip

You have until Friday to send it is correct, because your time lasts up to Friday. But the action itself takes by: Send it by Friday.

Answers

1. b) by. It's a deadline for one action: by.
2. a) until. Being at my desk lasts up to 6: until.
3. c) until. Your time lasts up to Friday: you have until Friday.

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