Grateful or thankful?

We use grateful to talk about how we feel when someone is kind to us or does us a favour:

[a message on a thank-you card]

Thank you so much for helping us move house. We are so grateful.

Love

Mark and Rose

[at the end of a formal letter]

I would be very grateful if you could send me more information about your company for my school project.

Not: I would be thankful …

We usually use thankful when we are relieved that something unpleasant or dangerous didn’t happen:

A:

I heard you were in an accident. Are you okay?

B:

I’m fine. There was some damage to the car. I’m just thankful that no one was injured.