What Is a Conditional Sentence?
A conditional sentence links a condition to a result using an if-clause and a main clause, such as "If it rains, the match gets cancelled." English has 4 types, numbered 0 to 3, plus mixed conditionals for combined time frames.
Every conditional sentence contains two parts: the if-clause and the main clause. The if-clause states a condition, and the main clause states the result. Word order stays flexible. You can write "If it rains, the match gets cancelled" or "The match gets cancelled if it rains" without changing the meaning.
English grammar recognizes 4 core conditional types, numbered 0 to 3, plus mixed conditionals. The CEFR framework, developed by the Council of Europe, structures how curricula introduce them: A1 and A2 learners start with the zero and first conditional for real, present-tense situations. B1 and B2 learners move into the second conditional for unreal present scenarios. C1 and C2 learners tackle the third conditional and mixed conditionals, which handle past regrets and complex hypothetical timelines.
Conditional structures appear regularly in B2 and C1 writing and speaking tasks, which is why examiners test them directly. Examinizer's free 25-question test takes 25 minutes and gives an instant level estimate. A certified result costs €8 (incl. 21% EU VAT = €9.68), delivered by email in 30 seconds. This is not a replacement for accredited exams like Cambridge or IELTS.
Conditional Types: Comparison Table (Zero to Third and Mixed)
Zero conditional (if + present simple, present simple) states facts with 100% certainty: "If you heat water to 100°C, it boils." First conditional (if + present simple, will + base verb) describes real future possibilities: "If it rains tomorrow, I will cancel the trip."
| Type | Structure | CEFR level | Meaning |
|---|---|---|---|
| Zero | if + present, present | A1-A2 | General truths |
| First | if + present, will + base | A2-B1 | Real future chance |
| Second | if + past, would + base | B1-B2 | Unreal present/future |
| Third | if + past perfect, would have + participle | B2-C1 | Unreal past, regret |
| Mixed | combines 2 time frames | C1-C2 | Past cause, present result |
Second conditional uses a past simple clause with would + base verb to imagine unreal situations: "If I had more time, I would learn Portuguese." Third conditional uses if + past perfect with would have + past participle to express regret about unchangeable past events: "If she had studied, she would have passed." Mixed conditionals combine two time frames, most often a past condition with a present result: "If I had taken that job, I would be living in Berlin now."
The conditional perfect form (would have + past participle) causes the most reported confusion among B2-C1 candidates, since it appears identically in both third and mixed conditionals. Distinguishing the two requires checking whether the if-clause describes a single past event or an ongoing state.
CEFR Level Breakdown: When Conditionals Are Taught (A1-C2)
Curricula introduce conditional forms in a fixed order. A1-A2 learners meet the zero conditional first ("If you heat ice, it melts") and then a basic first conditional for real future situations. B1 courses consolidate the first conditional and add the second conditional for hypothetical or unlikely scenarios ("If I won the lottery, I would travel").
B2 is where second and third conditionals get taught side by side, with contrast exercises forcing learners to choose between an unreal present ("If I were rich..") and an unreal past ("If I had studied.."). C1 material adds mixed conditionals, combining a past condition with a present result, plus finer control over conditional perfect forms. C2 covers stylistic inversion ("Had I known, I would have called") and formal or literary conditional structures rarely used in daily speech.
For the full sequence of tenses alongside conditionals, check our /grammar/tenses/ guide.
Common Mistakes with Conditionals
Four mistakes account for most conditional errors in B1-C2 writing samples reviewed by exam graders. Fixing these four covers the majority of conditional-related point deductions.
Mistake one: learners write "If it will rain, I will stay home" instead of "If it rains, I will stay home." The if-clause needs present simple even when the meaning is future. This error is common among A2-B1 candidates who translate directly from languages that allow future tense in the if-clause.
Mistake two involves the second conditional: students write "If I would have money, I would travel" rather than "If I had money, I would travel." Putting "would" in both clauses is a habit carried over from direct translation in several languages, including French and Spanish.
Mistake three confuses third conditional timing with conditional perfect constructions, mixing "If I had known" with "would have known" in ways that scramble past hypothetical sequences. This gets corrected around B2 level once students drill the fixed if + past perfect / would have + participle pattern.
Mistake four shows up in formal writing: wrong verb forms after "if" in passive constructions, such as "If the report is submit late" instead of "is submitted." Passive voice rules apply fully inside conditional clauses, covered in detail at /grammar/passive-voice/. Article errors before conditional nouns like "an opportunity" or "the outcome" also appear often; see examples at /grammar/articles/.
When to Use Each Conditional Type
Zero conditional fits scientific facts, instructions, and habits: "If you heat water to 100°C, it boils." Both clauses stay in present tense and describe something always true, not a one-time event.
First conditional fits realistic future plans or warnings, like "If it rains tomorrow, we'll cancel the trip." Second conditional fits hypothetical advice, dreams, or unlikely present scenarios: "If I won the lottery, I'd travel for a year." Third conditional expresses past regrets or criticism: "If she had studied, she would have passed." Mixed conditionals link a past decision to a present consequence: "If he hadn't quit his job, he'd be a manager now."
Confusing second and third conditional forms accounts for a large share of B1-B2 exam point losses, mainly because both involve "would" but attach to different time frames.
Test Your Conditional Level
Conditionals are not just an English-learner topic. Across the 16 languages studied for Examinizer's own keyword research, conditional-related grammar searches appeared in seven different languages, not just English. German accounted for the largest non-English share, at 12.8% of total conditional-related search volume, followed by Spanish at 9.8% and Italian at 5.7%, suggesting learners across multiple native languages struggle with the same structure.
Examinizer's free test checks which conditional level you've actually mastered in 25 questions and 25 minutes. A certificate costs €8 (incl. 21% EU VAT = €9.68), delivered by email in 30 seconds. It does not replace an accredited exam for university admission or immigration purposes, but it gives a fast benchmark of where you stand.
For cross-topic review, the full grammar library sits at /grammar/, covering everything from articles to modal verbs. To check where you stand on conditionals specifically, /english-grammar-test/ includes practice questions covering all four conditional types, scored instantly.