As If / As Though: Real and Hypothetical Comparisons

As if and as though are near-identical conjunctions that introduce a clause of manner or comparison, meaning roughly "in a way that suggests" or "in the way that would be true if". They are interchangeable in almost every context; as though simply sounds a little more formal or literary, especially in British English.

• It looks as if it's going to rain.
• It looks as though it's going to rain.

The tricky part is not choosing between the two conjunctions — it's choosing the right tense after them, because that tense signals whether the comparison is real and likely or hypothetical and unreal.

Real / Likely Comparison: Use a Normal Tense

When the comparison plausibly matches the actual situation, use the tense you would use normally — present, past, or whatever fits the real time reference.

• It looks as if it's going to rain. (a real, plausible prediction based on the sky right now)
• She sounds as if she's from Scotland. (a genuine guess about where she's actually from)
• He acted as if he was tired. (plausible — he probably really was tired)

Hypothetical / Unreal Comparison: Use the "Unreal Past"

When the comparison is clearly false, imagined, or contrary to fact, English switches to a past form even when talking about the present — the same "unreal past" pattern used after wish and in second/third conditionals. Use past simple for a present unreality and past perfect for a past unreality.

• He talks as if he knew everything. (but he doesn't — present unreal, so "knew" instead of "knows")
• She acted as if she hadn't heard the news. (but she had heard it — past unreal, so past perfect)
• You look as if you'd seen a ghost. (obviously you haven't literally seen a ghost)
• He spends money as if he were a millionaire. (he clearly isn't one)

Formal Subjunctive: "As If I Were"

In more formal or careful English, especially with the pronoun I, speakers use were instead of was after as if / as though — a leftover of the English subjunctive mood. In everyday spoken English, was is very common and widely accepted informally.

• He treats me as if I were a child. (formal / careful)
• He treats me as if I was a child. (informal, very common in speech)

"As If" as an Exclamation

As if can also begin an exclamation expressing strong disbelief or flat rejection of an idea — a very informal, spoken use unrelated to the comparison-clause pattern above.

• As if I would ever agree to that!
• A: Maybe he'll apologise. B: As if! (meaning "no way / that's never going to happen")

Real vs. Hypothetical: Comparison Table

Type	Time reference	Tense after as if / as though	Example
Real / likely	Present	Present simple/continuous	It looks as if it's raining.
Real / likely	Past	Past simple	He acted as if he was tired.
Hypothetical / unreal	Present	Past simple ("unreal past")	He talks as if he knew everything.
Hypothetical / unreal	Past	Past perfect	She acted as if she hadn't heard.
Hypothetical, formal, with "I"	Present	were (subjunctive)	He treats me as if I were a child.
Exclamation of disbelief	—	would / standalone	As if I would ever agree to that!

Common Mistakes

• Using present tense when the comparison is clearly false: If the situation is obviously untrue, the unreal past is required, not the present.
  Wrong: He talks as if he knows everything (but he doesn't).
  Correct: He talks as if he knew everything.
• Using present simple for a clearly false past event: A false past comparison needs the past perfect, not the past simple.
  Wrong: She acted as if she didn't hear the news (but she did).
  Correct: She acted as if she hadn't heard the news.
• Confusing "as if" with "like" + noun: "Like" is a preposition here and takes a noun phrase; "as if"/"as though" take a full clause with a subject and verb.
  Wrong: He acted like he was rich (informal, common in speech but not standard in formal writing).
  Correct (formal): He acted as if he were rich.
• Forgetting that "as if" can be real, not just hypothetical: Not every "as if" clause is unreal — if the comparison is plausible, a normal present or past tense is correct and does not need "were" or the unreal past.
  Correct: She looks as if she's enjoying herself. (genuinely plausible, ordinary present tense)

Practice Tips

• Compare with "wish": The unreal past after "as if" works exactly like the unreal past after "wish" and in second conditionals — if you're comfortable with "I wish I knew," you already know this pattern.
• Listen for "were": Notice when native speakers use "as if I were" in formal contexts (interviews, news, writing) versus "as if I was" in casual chat.
• Practise rewriting: Take real-tense sentences ("He is tired.") and turn them into both real ("He acts as if he's tired.") and hypothetical ("He acts as if he were tired," when he clearly isn't) versions to feel the contrast.

Practice Exercises

Explore related grammar topics:

All Grammar Topics Conditionals Wish / If Only Hypothetical Past Subjunctive Mixed Conditionals

Frequently Asked Questions

What is the difference between "as if" and "as though"?

There is virtually no difference in meaning — both introduce a clause comparing a situation to something real or imagined, and both follow the same tense rules. "As though" tends to sound slightly more formal or literary, especially in British English, but the two are interchangeable in almost every sentence: "It looks as if it's going to rain" and "It looks as though it's going to rain" mean exactly the same thing.

When do I use a normal tense after "as if"?

Use a normal present or past tense when the comparison is plausible or likely to be true. For example, "She sounds as if she's from Scotland" uses the ordinary present tense because it's a genuine guess about a real possibility. Similarly, "He acted as if he was tired" is fine with a simple past tense if he probably really was tired.

Why does "as if" sometimes use the past tense for present situations?

When the comparison is clearly false, imagined, or contrary to fact, English shifts one step into the past to signal unreality — the same "unreal past" pattern used after "wish" and in second conditionals. For example, "He talks as if he knew everything" uses "knew" (not "knows") because he clearly does not know everything; the past tense here marks the idea as untrue, not as referring to past time.

When should I use the past perfect after "as if"?

Use the past perfect when the false or imagined comparison refers to a past event rather than a present one. For example, "She acted as if she hadn't heard the news" (but she had heard it) uses the past perfect "hadn't heard" because the unreality is located in the past, one step further back than a simple past unreal comparison.

Is "as if I were" or "as if I was" correct?

Both are used, but they differ in register. "As if I were" uses the formal subjunctive mood, traditionally considered more correct and common in careful writing, exams, and formal speech: "He treats me as if I were a child." "As if I was" is extremely common in everyday spoken English and widely accepted informally, even though some style guides still prefer "were" with "as if" and "as though."

What does "as if!" mean as a standalone expression?

Used alone as an exclamation, "As if!" expresses strong disbelief or a flat rejection of an idea, roughly meaning "no way" or "that's ridiculous, it will never happen." For example, if someone suggests "Maybe he'll apologise," the reply "As if!" dismisses the idea as very unlikely. This use is informal and spoken, and is different from "as if" used to start a comparison clause.

What is the difference between "as if" and "like" as a comparison word?

"As if" and "as though" introduce a full clause with a subject and a verb: "He acted as if he was tired." "Like" is a preposition here and is followed by a noun phrase, not a clause: "He acted like a tired man." Using "like" directly before a clause ("He acted like he was tired") is very common in informal speech, but is generally avoided in formal writing in favour of "as if" or "as though."

Can "as if" be used with any tense, including future forms?

Yes, in principle any tense that fits the real time reference can follow "as if" for a real, plausible comparison, including present continuous, present perfect, or forms referring to the near future ("It looks as if it's about to start"). The key rule to remember is that the tense choice depends on whether the comparison is real/likely (use a normal tense) or false/imagined (shift into the unreal past).

How can I tell whether a comparison after "as if" is real or hypothetical?

Ask yourself whether the situation described could genuinely be true, based on context. If it's a reasonable guess or plausible explanation ("She sounds as if she's from Scotland" — she might really be), use a normal tense. If you already know the comparison is false or exaggerated ("He spends money as if he were a millionaire" — he isn't one), shift to the unreal past or use "were."

At what level are "as if" and "as though" typically taught?

The basic real-comparison use of "as if" and "as though" is often introduced around B1/B2 level, but the full hypothetical unreal-past pattern, including the formal subjunctive "as if I were," is typically taught at B2/C1 level, since it depends on learners already being comfortable with unreal past forms from conditionals and "wish" sentences.