Future simple for intentions (offers, promises and decisions)

The future simple tense is used to express future intentions that are decided at the time of speaking (spontaneous offers, promises and decisions):

Come on, I'll help you with those bags. (offer)
I will always love you. (promise)
I'll have a wiener schnitzel. (decision)

In the first person, shall can be used instead of will to announce intentions. Shall is more formal than will:

I shall definitely give up smoking this year.