40 questions on be going to vs will, focusing on when going to is needed: plans & intentions, evidence-based predictions; and when will is needed: spontaneous decisions, promises, opinions.
Use 'be going to' for a plan you made before you started speaking. Use 'will' for a decision you make as you speak. Five sentences need going to and five need will.
| Function | be going to | will |
|---|---|---|
| Pre-made plans | ✅ I'm going to study medicine. | ❌ |
| Spontaneous decisions | ❌ | ✅ I'll get the door. |
| Evidence predictions | ✅ It's going to rain! (clouds visible) | ❌ |
| Opinion predictions | ❌ | ✅ I think it will rain tomorrow. |
| Promises | ❌ (unnatural) | ✅ I'll be there. / I won't forget. |
| Polite offers | ❌ | ✅ Shall I / I'll carry that. |