It is vs This is

When to use each in English, with meaning, register, and examples.

It is

High-frequency chunk

This is

Top 1,000 (very common)
 It isThis is
Pronunciation🇬🇧 //ɪt ɪz//🇺🇸 //ɪt ɪz//🇬🇧 //ðɪs ɪz//🇺🇸 //ðɪs ɪz//
MeaningA way to say something is the case.A phrase used to introduce something or give an explanation.
ExampleIt is important to study for exams.This is the project I was telling you about.
RegisterNeutralNeutral
How commonHigh-frequency chunkTop 1,000 (very common)
CollocationsIt is true, It is time, It is clearThis is great, This is important, This is mine, This is how it works
Common mistakesOmitting 'is' when speaking., Confusing with 'there is' which has a different usage., Using 'it’s' incorrectly instead of 'it is' in formal writing.Omitting 'is' in informal speech, Using inappropriately in very formal presentations, Misplacing the phrase in a sentence
Usage notesUsed to make statements about existence or situations. It is appropriate in both spoken and written English. More formal alternatives exist in specific contexts (e.g., 'This is').Commonly used to point out or highlight something. It is appropriate in both formal and informal contexts.

See it in real clips

It is

Frequently asked questions: It is vs This is

What's the difference between It is and This is?

It is: A way to say something is the case. This is: A phrase used to introduce something or give an explanation.

Can you show an example of each?

It is: It is important to study for exams. This is: This is the project I was telling you about.

Can I use It is and This is interchangeably?

Not always. It is and This is are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.