I'll meet vs I'm meeting (2025)

Here's my explanation of the future in English:

• English has no future tense. It merely has a variety of strategies for referring to the future. Each of these strategies use the present tense in one way or another to refer to the future. The difference between them lies in the way they connect the present to the future.

• Events usually happen because a chain of events causes them to happen.

• Will suggests that
a) that chain of events has not begun before the moment of speaking, or
b) the chain of events is beginning at the moment of speaking, or
c) the chain of events is not discernible.
Example: At 4:48 Marty says to himself: 'I think I'll go to the pub tonight'. (Case b)

• Be going to suggests that the chain of events has begun, and implies that it's discernible.
Example: At 4:59 Marty calls that nice looking accountant in the next office and say 'Hey! You know what? I'm gonna go to the pub after work. D'you fancy coming?' (As a distant admirer of Marty, the nice looking accountant says yes.)

• The present continuous suggests not only that the chain of events has begun, but that it's progressed beyond being a mere intention and is now a plan.
Example: At 5:27 when Marty puts his coat on and his friend Brett asks him if he wants to get an Indian takeaway together, Marty says 'Nah! I'm having a drink with Trish from Accounting!'

• The present simple is used for anything that's written in a timetable.
Example: Three weeks later on a train to the Scottish Highlands for a cosy weekend in a castle, Marty asks, 'what time does the train get there?' and Trish answers, 'we arrive at 11:31.'

Will is the most complicated. It's used for subjective predictions because these are based on intuition rather than discernible chains of events:
A: So, who do you think will win the Premiership this year?
B: Oh, Manchester United will win. They always do. (Prediction based on my knowledge of Man Utd.)
vs.
B: Oh, Manchester United are going to win. They're already seven points up and they only need a draw against Chelsea. (Prediction based on the chain of Man Utd's performance.)

It'll rain tomorrow. (It always does in Manchester.)
vs.
It's going to rain tomorrow. (There's a cold front moving in and the clouds are gathering over the Atlantic.
The chain of events may have begun in the first case, but my use of 'will' shows that I'm not interested in them, or know nothing about them.)

The choice between will and be going to often doesn't make much difference:
Look at that scratch on my dad's car! He'll kill me!
vs.
Look at that scratch on my dad's car! He's going to kill me!

But sometimes it does. You can say:
Don't tell me what happens next! It'll spoil the rest of the film for me.
But you can't say:
Don't tell me what happens next! It's going to spoil the rest of the film for me.
because the going to implies the chain of events has begun at the time of speaking, whereas the 'don't tell me' makes it clear that it hasn't (and won't, if blabbermouth keeps his mouth shut).