Conditional Sentences | Types, Use & Examples

A conditional sentence describes a hypothetical situation and its potential consequence.

Conditional sentences always include both a dependent clause (also known as a subordinate clause) and an independent clause (also known as a main clause).

The dependent clause expresses a condition (e.g., “If I drink coffee”), and the independent clause describes the result of the condition (e.g., “I will be awake all night”).

In English, there are four primary types of conditionals, corresponding to different levels of possibility or likelihood.

Using conditional sentences

Conditional sentences are used to refer to a hypothetical scenario and its potential consequences. Every conditional sentence is a complex sentence made up of two clauses:

• A dependent clause (sometimes referred to as a conditional clause) that describes a condition that is unreal or has not yet happened (e.g., “If you study”)
• An independent clause that describes the result of the hypothetical condition (e.g., “you will pass the test”)

The conjunction “if” is usually used at the beginning of the conditional clause. The independent clause sometimes begins with “then” (e.g., “If you go skiing, then you will need to buy goggles”), but including “then” is not required.

If the dependent clause is placed at the beginning of the sentence, a comma is required after the clause. However, if the independent clause appears first, no comma is required (and “then” should not be used).

When the order of the clauses in a conditional sentence is changed, the nouns and pronouns may also need to be changed.

Zero conditional sentences

The zero conditional is used when communicating facts, habits, or general truths. The independent clause and the conditional clause are generally in the simple present tense in zero conditional sentences.

Because zero conditional statements refer to general truths rather than specific scenarios, “when” can be used instead of “if” in the conditional clause.

When zero conditionals are used to give advice or instructions or to make a command or request, the simple present tense is used for the conditional clause, and the imperative mood is used for the independent clause.

First conditional sentences

First conditional sentences indicate a realistic potential action in the present and its probable result. The two clauses of a first conditional sentence follow a specific pattern:

• The conditional clause contains a verb in the simple present tense (e.g., “if it rains”).
• The independent clause contains a modal verb (usually “will,” “might,” “may,” or “can”) and the infinitive form of the main verb (e.g., “walk”).

Second conditional sentences

The second conditional is used when referring to an impossible or improbable present or past condition and its unrealistic or unlikely result. The two clauses of a second conditional sentence follow a specific pattern:

• The conditional clause contains a past subjunctive verb form (e.g., “snowed”).
• The independent clause contains a modal verb (usually “would,” “might,” or “could”) and the infinitive form of the main verb (e.g., “play”).

Third conditional sentences

The third conditional is used when describing an unreal past condition and its past consequence. The two clauses of a third conditional sentence follow a specific pattern:

• The conditional clause contains a past perfect tense verb (e.g., “if I had known”).
• The independent clause contains a modal verb (usually “would,” “might,” or “could”), the auxiliary verb “have,” and the past participle of the main verb (e.g., “play”).

Mixed conditional sentences

Mixed conditional sentences combine the second and third conditionals. There are two types of mixed conditionals. The first type describes an unreal past condition and its ongoing result. The two clauses of this type of mixed conditional sentence follow a specific pattern:

• The conditional clause is formed like the third conditional, with a past perfect tense verb.
• The independent clause is formed like the second conditional, with a modal verb (usually “would”) and the infinitive of the main verb.

The second type of mixed conditional sentence refers to an unreal past condition and its past result. The two clauses of this type of mixed conditional sentence follow a specific pattern:

• The conditional clause is formed like the second conditional, with a verb in the past subjunctive form.
• The independent clause is formed like the third conditional, with a modal verb (usually “would”), the auxiliary verb “have,” and the past participle of the main verb.

Inverted conditionals

In more formal situations, people sometimes use an inverted conditional. This involves inverting the subject and auxiliary verb of the “if” clause and omitting the “if.”

A common type of inverted conditional includes the word “should.” In these cases, it seems like “if” is being replaced by “should.” In reality, this is a type of inversion, as the example below demonstrates.

Frequently asked questions about conditional sentences

What is a conditional clause?

A conditional clause is one of the two clauses used in a conditional sentence. It is a type of dependent clause (also known as a subordinate clause) that describes a hypothetical situation.

Conditional clauses typically begin with the conjunction “if.” They are connected to an independent clause (also called a main clause) that describes the potential results of the hypothetical scenario (e.g., “If it snows, school will be canceled”).

What is the first conditional?

The first conditional is a type of conditional sentence that describes a realistic potential action in the present and its probable result (e.g., “If you try your best, you will succeed”).

All first conditional sentences are made up of two clauses:

• A dependent clause that contains a verb in the simple present tense (e.g., “if you try”).
• An independent clause that contains a modal verb (usually “will,” “might,” “may,” or “can”) and the infinitive form of the main verb (e.g., “succeed”).