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Future Time Clauses: When, As Soon As, Before
Why it's 'I'll call you when I get there', not 'when I will get there': the future goes in the main clause, a present tense in the time clause.
Both halves of I'll call you when I get there are about the future, but they use different forms. The main clause can carry will or another future meaning; the time clause after when, as soon as, before, after or until normally takes a present tense, even though the event hasn't happened yet. The useful habit is simple: recognize the time clause before choosing the verb form.
The pattern
A future meaning in the main clause, a present tense in the time clause. The order of the two halves doesn't matter. The main clause may use will, going to, a modal, or an imperative.
The conjunctions that behave this way: when, as soon as, before, after, until, till, once, by the time, the moment. If works the same way in a first conditional, which is why the two topics feel related.
Present perfect for "finished first"
You have a second option in the time clause. Use the present perfect when you want to stress that the first action is completely done before the second starts.
When I finish the report, I'll send it over. (same meaning, slightly plainer)
Both forms are correct in most sentences, so this isn't a choice to agonize over. The present perfect earns its place when the sequence genuinely matters — a report half-written can't be sent.
When "when" does take will
This is the exception worth knowing — otherwise you'll "correct" sentences that were right. When has a second job: it can introduce an indirect question, and there will is perfectly normal.
I'll start cooking when he arrives. (time clause — "at the time that he arrives")
A quick test. Try replacing when with at the time that. If the sentence still makes sense, it's a time clause and takes the present. If it doesn't, you have an indirect question, and will is fine.
I'll get off when the train stops. (at the time that → present)
There's one more case, rarer in speech: will can appear in a clause when it means willingness rather than future time — If you'll wait here, I'll get the manager. You don't need to produce it, but it explains sentences that would otherwise look wrong.
Common mistakes
Will in a normal future time clause. After when, as soon as and similar conjunctions, use a present tense for future time.
✓I'll call you when I get home.
Will in both halves after as soon as. Same rule, different conjunction.
✓As soon as the meeting finishes, I 'll send the notes.
Will after until in a normal future time clause. The clause after until normally uses a present tense.
✓I won't leave until she comes back.
Question word order inside an indirect question. Keep statement order after when: subject before will.
✓Nobody knows when the results will come out.
Quick exercise
Put the verb in parentheses into the right form. One item is an indirect question, so read each sentence before you answer.
- I'll text you as soon as I ___ (land).
- We won't start until everyone ___ (be) here.
- Call me before you ___ (leave) the office.
- I wonder when she ___ (send) the final version.
- When I ___ (finish) this report, I'll send it over.
- By the time you ___ (get) home, dinner will be ready.
Answer key
- land (future time clause after as soon as → present)
- is (future time clause after until → present)
- leave (before + present, even though the main clause is an imperative)
- will send (indirect question after wonder — not a time clause)
- finish ("'ve finished" is equally correct and stresses completion)
- get (by the time + present)
Practice this in Recursio
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