Be going to / Will Summary Sheet

Will: (event decided on speaking, ‘consequential’ or public timetables)	Be Going To: (event decided earlier, based on current evidence or emphatic)
I will leave tomorrow. We will leave at 5. What will you eat? I won’t leave tomorrow. May sometimes be interchanged with be+ going + to + verb With temporal modifiers	I am going to leave tomorrow. We are going to leave at 5. What are you going to eat? I am not going to leave tomorrow. Be agrees w subject; Gonna for speech; Strong association with present
Spontaneous decisions made at time of speaking; I am hungry, I will go home to eat. In response to complaints, requests or to make offers, promises, or show willingness Jo, we are low on dog-food. No problem, I’ll get some on my way back.	Previously formed intentions, plans; decided before speaking It is dinnertime, I am going home to eat. Jo, we are low on dog-food. I know, I am going to get some on my way back.
Expresses facts. The geese will return this autumn.	But also The geese are going to return this autumn.
For scheduled events The tennis match will start at 1 pm.	But also The tennis match is going to start at 1 pm
Less emphatic than the periphrastic form They will enjoy the film (I think)	Stronger than will They are going to enjoy the film (for sure).
Predictions without evidence. They will have children (some day). It looks grey; it will rain, but the wind may blow the clouds away . Prediction without specific time. She will travel (one day). Prediction is about others They will finish tomorrow.	Predictions based on present evidence She is going to give birth in June. Something is inevitable, likely to happen Those clouds are about to burst. It is going to rain in a few minutes. Prediction is about oneself, personal schedule I am going to Europe this summer.
Planned, but the intention is not yet formulated I will buy a new PC (when this one crashes, some time later)	Certainty, plan is made and intention is formed I am going to buy a new PC (for sure, soon)