Many of my clients often confuse these two words “by” and “until” especially in their written English.

Take a look at these two sentences:

  • You have until Friday to submit your sales report
  • You have to submit your sales report by Friday

In both these sentences, the deadline is Friday and no later. However, there is a difference in how these two words are used. Let’s take a look at this difference.

Until – describes a period of time before the deadline. In other words, up to a particular time.


  • You have until Friday to submit your expenses (no later than Friday)
  • We have until the end of March to complete the plans for the project (the deadline is the end of March and not later)

Until  also describes the situation or state up to a particular time.


  • I worked until 7pm last night.
  • I shall work on this report until lunchtime. (the report may be finished or not. It doesn’t matter)
  • The shipment will not arrive until the end of next week.


By – is a time preposition and means “on” or “before”. It tells you when.


  • I need those sales figures by 5pm (on or before but no later)
  • I need to leave the office by 4pm if I am to catch my train. (on or before)
  • Please reply to our invitation by 23 November.

Over to you:

Choose the correct answer

1. If you call me by/until 6pm, you will probably find me in the office.

2. The firm’s new accountant won’t be able to start by/until his other contract ends.

3. The company will not respond to any applications by/until the end of the closing date.

4. Reservations for the Board Room must be submitted to Reception by/until the close of business.

Answers: Drop me a line in the comments box below for the answers.
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