BY & UNTIL Can You Use These Prepositions CORRECTLY?
Are you using BY & UNTIL correctly? These English prepositions can be a little tricky – they are similar, but not the same!
➡️ I’ll be home by 9
➡️ I’ll be home until 9
What is the difference? Let’s practise!
In this lesson today, we’re going to focus on two really important English prepositions, prepositions that sometimes get confused, by and until.
These are prepositions of time and they can be used in a similar way but the biggest mistake that my students make is using by and until in the same way. They are not interchangeable.
In fact, in some situations, they can have a completely different meaning but don’t worry at all. Today you’re here to learn how and when to use these prepositions correctly. Plus, I’ve included a little test at the end so that you can make sure that you’re using these prepositions accurately.
Is that okay? Good! Let’s dive in!
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By means at or before a certain time.
- Shah will be at the party by 5pm.
The preposition by helps us to know that he will be there at 5pm. Whether he arrives before it or exactly at that time, he won’t arrive after 5pm.
Now until shows us a state or a situation that continues up to a certain time.
- Can you wait till I get there to cut the cake?
Waiting is the situation and it’s going to continue up until the moment that Shah arrives. When Shah arrives, the waiting stops and in this case, we get to eat cake.
When you hear a native English speaker using this word you’ll notice that often it’s reduced.
Until becomes till.
It’s unstressed so it’s not an important word in our sentence. It reduces down. And so for that reason, it could be a little difficult to hear unless you know what you’re listening for.
- I’ll wait till five but then I’m gonna cut the cake without you.
So there’s no difference in the meaning between until and til, til is just easier to say, it flows a little more naturally so you should try it out when you’re speaking.
By and until are really useful when you’re talking about deadlines.
- I have to decide by Monday.
I have to decide on or before Monday. I can’t decide after Monday because by then it’s going to be too late. Monday is the deadline. So we use by plus time or date or day to talk about a deadline.
And the focus really is on that endpoint, the moment when the task must be complete or the action needs to be complete.
But we can also say:
- I have until Monday to decide.
So the meaning here is very similar but it’s not exactly the same because with until, the focus is on the period of time leading up to the endpoint. So you have a period of time to decide from now until Monday.
So with until, we’re really focusing on that block or that section of time before the deadline. But with by, we’re focused on the endpoint.
Now I think an easy way to remember the difference is to think about the time expression from something until something or till something.
So let’s look at this example again.
- I have from today till Monday to decide.
You can see that the beginning of that block of time is really clearly defined and the end is really clearly defined as well in this expression. We know from now till Monday.
When we say: I have until Monday.
It’s basically the same as saying from now until Monday but here the starting time is either not important or it’s not relevant or we just assume that the time is from now.
- The party goes til late.
It’s not important what time the party starts. We’re emphasising that the party continues into the night.
- I’ll be here till midday.
This just means I’ll be here from now until midday.
Okay this is important to keep in mind. Both by and until can be used with a precise time, an exact time.
- I need the contract by 5 o’clock.
- You have until 2pm to sign the contract.
However only until can be used with less precise time expressions.
- He didn’t get home until late.
Late is a time expression but it’s not a precise time, it’s a general time. We don’t really know whether late means 2am or 9pm but you get the idea.
We can even use until together with a second action or event.
- I’ll wait until you get here.
- He watched TV until he fell asleep.
- Bake the cake until it’s golden brown.
So in all these examples, until is actually a conjunction. A conjunction is a linking word that helps to join two clauses or sentences together and that is why we can’t simply replace until with by in any of these examples. It doesn’t make sense.
Let me show you how easy it is to get confused by by and until.
Do they mean the same thing? They do not. They don’t mean the same thing but do you know the difference?
- I’ll be home by nine.
So I’m not home now but in the time between now and 9 o’clock, I’ll arrive home. So if you come to my house after nine, that’s where I’ll be.
- I’ll be home until nine.
Usually means I’m home now. So I’ll be at home from now up until nine. If you come to my house after nine, I won’t be there. So the meaning here is almost completely opposite in these sentences.
That’s why you need to think carefully about using by or until because you can see that it’s easy to make the wrong choice and that really could lead to a misunderstanding.
Okay so let’s test what you know. I’ve prepared a little quiz to help you test your skills to make sure that you really understand these prepositions. You’ll see a sentence up on screen just like this. All you need to do is decide whether by or until is the right way to complete the sentence.
This one is by because the letter could arrive on or before Tuesday. And the verb arrive helps us to know that we’re focusing on Tuesday as the deadline.
- The letter should arrive by Tuesday.
So are you ready to start the quiz? It’s your turn now.
- The report is due by Friday.
- I waited until 9:30 but no one showed up.
- I need to be at the airport by 12 because the flight departs at 1:30.
- I forgot my keys, can you wait there until I get home?
- The shops stay open until 9pm on Thursday.
So how did you go? Did you get all of them right? Let me know down in the comments or if you have any questions about the quiz, let me know.
Learning to use English prepositions correctly really does take practice and patience.
But if you want to dive deeper and perfect your English prepositions with me then go and check out my Prepositions course. For all of my students here on YouTube, I’ve got a twenty per cent discount for you. Make sure you use this code at the checkout. The link to my prepositions course is down in the description below.
Thank you for practising with me today and for all of your support, I really appreciate it.
I’ll see you in the next lesson!
Links mentioned in the video
How To Ask Great Questions in English
EACH & EVERY | English Grammar Lesson
Subject-Verb Agreement | English Grammar Lesson | Fix Common Mistakes