Should you promise to finish your homework by next week or until next week? Will you send somebody an email by or until tomorrow? Many learners find these two words confusing, particularly because some languages such as German use the same word for both concepts. Here’s a short explanation of the key differences.
“By” describes the time before which something is completed. For example, in the sentence “Please finish your homework by Friday”, the homework can be finished on Tuesday, Wednesday, Thursday, any time before Friday. The important thing is that it is finished before then; exactly when is not relevant.
- I need to finish my project by the end of the week.
- We must deliver the parcel by this evening.
- You need to book the tickets by Wednesday to get a discount.
- Could you send me the information by Saturday?
“Until” describes an action that is in progress and will remain in progress up to a point. For example, “I worked until 5 o’clock yesterday” means the working was an ongoing process that continued until 5 o’clock and only stopped at that time. I could also say, “My friend is on holiday until Friday”. They are on holiday now and will stop being on holiday on Friday.
- I will be in a meeting until 5pm this afternoon.
- They’re staying in Madrid until Sunday.
- We will be on the train until midday.
- The party will last until midnight.
Can you think of any more examples with by and until? Or do you have any more questions about this subject? Share them in the comments below.