Casa ESL · grammar guides · level A2–B1
First Conditional — Complete Guide with Examples
The first conditional talks about real future possibilities: If it rains, we'll stay home. One clause sets the condition (if + present simple), the other gives the result (will + verb).
Form and the golden rule
If + present simple, will + base verb: "If you study, you'll pass." The clauses can swap order — "You'll pass if you study" — with no comma needed when if comes second.
The golden rule: no will inside the if-clause. English marks the future once. "If it will rain" is the single most common conditional error on earth; the correct form is "If it rains."
Friends of the first conditional
Unless = if not: "Unless you hurry, we'll miss the train" (= if you don't hurry). As soon as, when, until, before, after follow the same rule — present tense inside, future outside: "I'll call you when I arrive" (not "when I will arrive").
The result can also use imperatives or modals: "If you see Anna, tell her." / "If it snows, we might cancel."
| Pattern | Example |
|---|---|
| If + present, will | If she calls, I'll answer. |
| Will … if + present | I'll answer if she calls. |
| Unless | We'll be late unless we leave now. |
| When/as soon as | I'll text you as soon as I land. |
| If + present, imperative | If the alarm rings, get out fast. |
Common mistakes
✓ If it rains, we will cancel.
No will in the if-clause.
✓ I'll call you when I arrive.
Future goes in the main clause; present after when.
✓ Unless you hurry, we'll be late.
Unless already means if not — no double negative.
Practice
- If you ___ (heat) ice, it ___ (melt).
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heat, will melt (or melts — zero conditional also correct) - She ___ (be) angry if you ___ (forget) her birthday.
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will be, forget - I'll wait here until the shop ___ (open).
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opens - ___ you ___ (help) me if I ___ (ask) nicely?
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Will you help, ask
FAQ
What is the first conditional?
A structure for real future possibilities: if + present simple in the condition, will + base verb in the result. If it rains, we'll cancel the picnic.
Can I use will after if?
Almost never. The if-clause stays in the present simple even though the meaning is future: "If she comes, I'll be happy," not "If she will come."
What is the difference between first and second conditional?
First conditional = realistic future (If I win, I'll celebrate). Second conditional = imaginary or unlikely present/future, using past forms (If I won the lottery, I'd travel the world).
Want this to actually stick?
One-on-one lessons with a real teacher, or free worksheets for this level — your pace, your goals.
More guides: Present Simple · Past Simple · Present Continuous · Present Perfect