Writing Tip: When should you use “that” and “which”?

It is often a matter of judgement, but mostly you use “that” when you are differentiating one thing from others like it. By contrast, you use “which” with a comma before it, when you are talking about one specific item.

Hopefully, these examples will help:

Example A: I will show you the cakes that arrived from grandma.(I'm differentiating grandma’s cakes from the ones that were made by other people.)

Example B: The cakes, which are in the basket, are from grandma.(I'm referring to a specific lot of cakes.)

Another way to approach these words is to think about what is essential and what is non essential.

The word “that” begins an essential clause - it is essential to the sentence. (Check Example A)

In Example B, the part of the sentence starting with “which” is non essential. You could remove the words “which are in the basket” without changing the meaning of the sentence.