Future plans – Be going to
Be going to and will are grammatical structures used to talk about future plans, predictions or promises. Be going to is used to talk about plans and intentions, is also used informally for making predictions.
In Grammar Box 1 you can observe the grammatical rules for different uses of be going to. Remember that when we use verbs in infinitive form we do not add -ing or -ed.
People from different places and different ages make plans. People consider different aspects of the future from short-term or long-term; to tomorrow´s weather; to new technology in the future and how it will affect us. It is important to learn how to talk about plans; this may help you organize different goals.
Time expressions are words used at the end or at the beginning of a sentence. In block II, you learned some time expressions mostly used for actions in the past. In Grammar Box 2, you will find some time expressions used for the future.
Auxiliary will – Predictions
Another grammar structure used to talk about the future time is will. Will is an alternative for going to when making predictions. Will is a little more formal than going to for predictions. Will is also used to talk about decisions made at the moment of speaking. In a daily conversation will is generally used in contracted form. Using the full form usually makes the speaker sound more formal.
In Grammar Box 3 you can see the use of will for predictions.
Fuente: Secretaría de Educación Pública. (2015). Lengua adicional al español II. Ciudad de México.