The Difference between ‘that’ and ‘which’

‘That’ and ‘which’ are both used to refer to things, people and places. However, they are used in different ways and within different contexts. If you were to get mixed up when using ‘that’ and ‘which’ you would still be understood though.

THAT
To indicate a person, thing, idea, state, event, time or remark.
That is her mother in the green dress.
It was that kind of tea I was wanting.
Look at that car!
He was in that house when I last saw him.

‘That’ can also be used when a thing or person is not near to the speaker.
Look at that boy over there.
Can you pass me that glass.
Go to that house beside the bridge and turn left.
She made that beautiful vase over there.

To indicate one of two or more persons, things, etc., already mentioned or referred to.

‘That’ can be used to distinguish between two or more things, persons etc that the person already knows about or has been referred to before.
This is my sister and that is my cousin.

That is my work and the work over there is his.

This is for today and that is for tomorrow.

I am going to wear this top tonight and save that good suit for next week.

He can eat this sandwich just now but cannot eat that pear till it is ripe.
Do you remember that dress I was talking about.
Last night the food was wonderful at that restaurant I went to.

‘That’ can also be used to emphasize something.

I was that scared that I couldn’t go in the house.
It was that cold, I had to put on four jumpers!
To indicate a contradiction.
Not this book, but that book.
I don’t want this glass, I want that one!
Pass that bowl over, rather than the one I have.

WHICH
To indicate a decision between different options
In contrast, ‘which’ is used in questions when asking someone to choose between a limited number of options.

Which do you enjoy more, tennis or football?
Which cake would you like, the sponge cake or the carrot cake?
Which do you prefer, the blue or the pink wallpaper?
Which of these do you want?
Which of these do you need?
Which colour would suit you best?

To refer to a specified time, event, person or thing

‘Which’ can also be used to be specific about a thing or meaning.
The movie, which I watched last night, was brilliant.
The ideas which she believed were very honourable.
The magazine included four stars, of which two were musicians.
Houses which are in the countryside are cheaper than city houses.
Cars which are run on electricity are just as reliable as cars which run on petrol.

To indicate a thing or fact or to give more information about something.

His new book, which won four awards, was a best seller.
Her new blouse, which only cost £3, was really pretty.
The television studio, which was local, was very successful.
He was at the shop for ages, which was good, because I had a lot to do.
They had £10, which was not going to be enough, as the lunch cost £15.
The movie, which won several awards, was on last night.

Often ‘which’ and ‘that’ are both acceptable and grammatically correct, but it can make the meaning of the sentence subtly different. A good way to help is use ‘which’ if a group of words adds information and use ‘that’ if it limits the set of things you’re talking about.