B1 · Intermediate

Conditional Sentences

Use if to express timeless facts and real future possibilities — the zero and first conditional cover everything from scientific laws to weekend plans.

Level: B1 Zero & First conditional Play · Practise · Score

The Grammar Transformer

Choose a type. A subject. A scenario.

Two conditional types, four subjects, three scenarios — 24 combinations. Swap between Zero and First to see exactly how the if-clause stays the same while the result clause changes.

If it rains tomorrow, we will stay inside.

Structure:if + present simple , subject + will + base verb

First conditional: a real, possible future situation. The if-clause always uses present simple — never will. The result uses will + base verb.

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The rules — with examples

The two forms, when to use each one, the common mistakes to avoid, and the time signals that go with the first conditional.

The two forms

Type 0

Zero Conditional

if + present simple , present simple

For timeless facts, general truths, and habits. The result always follows the condition — no exceptions, no time limit.

If you heat water to 100°C, it boils.
If I eat too much sugar, I feel sick.

Type 1

First Conditional

if + present simple , will + base verb

For real, possible future situations. The speaker believes the condition could genuinely happen. The result is a likely consequence.

If it rains tomorrow, we will cancel the picnic.
If she studies hard, she’ll pass the exam.

Zero vs. First — what’s the difference?

Zero — always true

If you heat ice, it melts.

If plants don’t get water, they die.

Meaning: This happens every single time, without exception — a law of nature, a scientific fact, or a personal habit.

First — real future

If it rains tomorrow, we will stay inside.

If she doesn’t hurry, she will miss the bus.

Meaning: This might happen in the future. The speaker thinks it is a genuine possibility, not just imaginary.

Common mistakes

If it will rain, we’ll stay home. → If it rains, we’ll stay home.

Never use will in the if-clause of a first conditional. The condition uses present simple.

If I would win, I would travel. → If I win, I will travel.

Would belongs in the second conditional (imaginary). For a real future possibility, use will in the result clause.

If you will heat ice, it melts. → If you heat ice, it melts.

Zero conditional: both clauses use present simple. No will anywhere.

When it rains tomorrow, we’ll cancel it. → If it rains tomorrow, we’ll cancel it.

Use if for uncertain future events. When assumes the event will definitely happen.

First conditional time signals

Words that often appear with the first conditional

tomorrow next week / month / year soon later this evening one day unless (= if not)

Practise & score yourself

Ten questions — five multiple choice, five gap-fill. Instant scoring and a short explanation for every answer.

Your score

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The one rule to remember

Zero conditional = always true — use present + present for facts and habits that have no exceptions. First conditional = real future possibility — use present + will for things that could genuinely happen. And in either conditional, the if-clause never takes will.

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