Grateful is the normal word for people's reactions to kindness, favours etc. In other words we use grateful to talk about how we feel when someone is kind to us or does us a favour. A person, who is grateful, is appreciative of benefits received.
For instance:
- I'm very grateful for all your help. ( NOT I'm very thankful....)
-She wasn't a bit grateful to him for repairing her scooter.
- I am extremely grateful to all the teachers for their help.
- We would be grateful for any information you can give us.
On the other hand, 'thankful' is used especially for feelings of relief at having avoided a danger, or at having come through an unpleasant experience. A thankful person is pleased about something good that has happened, or something bad that has not happened.
For example:
For example:
Peter: I heard you were in an accident. Are you okay?
Bob: I’m fine. There was some damage to the truck. I’m just thankful that no one was injured.
I was thankful to see they'd all arrived safely.
I'm thankful that we got home before the storm started.
We feel very thankful that he didn't marry her after all.
I hope the aforementioned information was of some help.