A prediction is a statement about what you believe or expect will happen in the future. It is based on your opinion, knowledge, experience, or general understanding of a situation — not on hard facts or certainties. Because predictions express what someone thinks or believes about the future, they naturally pair with will.
This is one of the most common uses of will in everyday English — and in academic, journalistic, and professional writing. Whenever you express a view about the future using language like I think, I believe, I expect, I'm sure, probably, definitely, I doubt, the main verb that follows takes will.
These expressions are the clearest signals that will is required for a prediction:
Adverbs like probably, definitely, certainly, never, and perhaps go between will and the base verb in affirmative sentences — and before won't in negatives:
Both will and going to can be used for predictions, but the basis of the prediction determines which one to use:
| WILL — opinion-based prediction | GOING TO — evidence-based prediction |
|---|---|
| Based on opinion, belief, or general expectation | Based on visible present evidence you can see right now |
| No specific present evidence — just what you think | Something observable now makes the future outcome clear |
| "I think it will rain later." (my opinion) | "Look at those clouds — it is going to rain." (I can see them) |
| "I believe she will win." (my view) | "She's running so fast — she is going to win!" (I can see it) |
| "Scientists think temperatures will rise." | "The data shows temperatures are going to rise." (current data) |
In practice, the distinction is often about immediacy. Going to predictions tend to be about what you can see happening right in front of you — the evidence is immediate and undeniable. Will predictions tend to be about broader, less certain expectations about the future.
In English, negative predictions typically use I don't think + will — not I think + won't. The negation goes on think, not on will:
✗ I think she is going to pass the exam. · In my opinion, the economy is going to recover. · I believe technology is going to change everything.
✓ I think she will pass the exam. · In my opinion, the economy will recover. · I believe technology will change everything.
When the prediction is introduced by I think, I believe, In my opinion, I expect, I'm sure, or any similar expression of personal view, use will. These phrases signal that the prediction is based on opinion — not on something you can see right now. Going to is for predictions triggered by visible present evidence, not personal belief.
✗ Look at those clouds — it will rain! · Watch out — he will fall! · The fuel gauge is empty — we will run out of gas.
✓ Look at those clouds — it's going to rain! · Watch out — he's going to fall! · The fuel gauge is empty — we're going to run out of gas.
When you can see clear present evidence that makes a future outcome obvious and immediate — dark clouds overhead, someone about to fall, a gauge reading empty — use going to. The evidence is visible right now, not a matter of opinion. Will sounds too uncertain or personal in these situations.
✗ Technology will changed everything. · The economy will to recover. · Prices will rises next year. · She will winning the race.
✓ Technology will change. · The economy will recover. · Prices will rise. · She will win.
After will, always use the base form of the verb — the infinitive without to. Never use to + infinitive, the Past Simple, the -ing form, or the third-person -s ending. Will is a modal auxiliary and modals are always followed by the base form: will change, will recover, will rise, will win.
✗ She probably won't be happy about this → should be: She probably won't be... ✓ (actually this is correct)
✗ She will be probably late. · Probably she will not come.
✓ She will probably be late. (probably between will and base verb)
✓ She probably won't come. (probably before won't in negatives)
✓ It will definitely rain. · He will certainly succeed.
In affirmative sentences, adverbs like probably, definitely, certainly go between will and the base verb: will probably be, will definitely pass, will certainly arrive. In negative sentences, they go before won't: probably won't come, definitely won't agree. Placing the adverb after the base verb (come probably) or after the whole sentence (She will come, probably) sounds unnatural in standard English.