Is it correct grammar to say 'It will be I?

Answer 1

Yes, 'It will be I' is correct grammar. The verb 'to be' takes a complement, not an object. Hence:

'Which girl is your sister?' 'That is she.' (Not 'That is her.')

'It was they who stole the money.' (Not 'It was them'.)

'Will it be we who cook dinner?' (Not 'Will it be us?')

'Who will make the opening remarks?' 'It will be I.' (Not 'It will be me.')

Having said that, while the above examples are correct grammar, it is much more common in colloquial speech to use the object form of the pronoun (the form shown in brackets above) rather than the complement. To avoid having to make the choice at all, you could recast the sentence. In the above examples, you might end up with:

'Which girl is your sister?' 'That one.'

'They stole the money.'

'Will we cook dinner?'

'Who will make the opening remarks?' 'I will.'

Answer 2

Yes, "It will be I" is correct, but it is not always used, because some people think it sounds overly formal and stiff. While technically not correct, "It will be me" is often used instead, especially informally.

Answer 3

While some may consider it formal or old-fashioned, "It will be I" is correct grammar. It is an example of using the subjective case ("I") after a linking verb like "to be." In more informal or everyday language, you may hear "It will be me," which is also widely accepted.