Formal vs Informal Grammar: When Rules Bend

Understand when grammar rules are strict and when they bend — formal vs informal English for exams, essays, and everyday communication.

May 17, 2026 Updated on May 17, 2026 Confusing Words , Exam Grammar 7 min read

Consider these two sentences:

Formal: I am going to the store. Do you require anything?
Informal: I’m gonna hit the store. Need anything?

Both communicate the same idea. But the grammar is different — and each version is correct in its own context.

The problem arises when students use informal grammar in formal writing, or hyper-correct formal grammar in casual conversation. This article explains when grammar rules are strict, when they bend, and how to choose the right register.

Rule box: Grammar choices shift by context. Use formal grammar for exams, essays, official emails, and professional writing. Use informal grammar for conversation, text messages, and casual writing. The key is knowing which structures belong where.

Contractions (I’m, don’t, can’t, won’t, it’s) are standard in speech and informal writing. In formal writing, write the full form.

Informal	Formal
I’m happy.	I am happy.
Don’t worry.	Do not worry.
Can’t you see?	Cannot you see? / Can you not see?
It’s raining.	It is raining.
We’ve finished.	We have finished.

Exam note: In school essays, exam answers, and formal letters, avoid contractions. Write do not instead of don’t, cannot instead of can’t.

In informal English, it is perfectly acceptable to end a sentence with a preposition. In formal English, the preposition is often fronted.

Informal	Formal
Who did you speak to?	To whom did you speak?
This is the book I was looking for.	This is the book for which I was looking.
Who are you waiting for?	For whom are you waiting?
That’s something I can’t put up with.	That is something with which I cannot put up.

Note: The “never end a sentence with a preposition” rule is a myth. Both forms are grammatically correct. The formal version sounds more polished; the informal version sounds more natural. Choose based on context.

In formal English, who (subject) and whom (object) are distinguished. In informal English, who is used for both.

Informal	Formal
Who did you give it to?	Whom did you give it to? / To whom did you give it?
Who are you calling?	Whom are you calling?
Who did you see?	Whom did you see?

Tip: If you can replace the word with him/her/them, use whom. If you can replace it with he/she/they, use who.

You gave it to him → Whom did you give it to?
He called you → Who called you?

In formal English, can refers to ability and may refers to permission. In informal English, can is used for both.

Informal	Formal
Can I come in?	May I come in?
Can I borrow your pen?	May I borrow your pen?
She can swim. (ability)	She can swim. (ability — same in both)

Exam note: In formal writing and exams, use may for permission and can for ability.

In formal writing, every sentence must be a complete clause with a subject and a verb. In informal writing and conversation, fragments are common and acceptable.

Informal (fragment)	Formal (complete)
Because I was tired.	I left early because I was tired.
No way.	That is not possible.
Of course.	Certainly. / Of course, I agree.
Not a chance.	There is no chance of that happening.

Exam note: Never use sentence fragments in exam answers or formal essays. Every sentence must have a subject and a finite verb.

These informal reductions are standard in speech but unacceptable in formal writing.

Informal	Formal
I’m gonna go.	I am going to go.
I wanna help.	I want to help.
I gotta leave.	I have got to leave. / I must leave.

Informal speech uses fillers (like, you know, basically, actually, I mean) that are inappropriate in formal writing.

Informal	Formal
I was, like, really angry.	I was extremely angry.
Basically, the plan failed.	In essence, the plan failed.
It was, you know, unexpected.	It was unexpected.

What is the context? Exam/essay → formal. Conversation/text → informal.
Are you using contractions? Formal: avoid. Informal: fine.
Are you ending with a preposition? Formal: front it if possible. Informal: acceptable.
Who or whom? Formal: distinguish. Informal: who is fine.
Can or may? Formal: may for permission. Informal: can is fine.
Are there fragments? Formal: never. Informal: acceptable.
Gonna/wanna/gotta? Formal: always expand. Informal: fine in speech.

Informal: I’m gonna help. → Formal: I am going to help.
Informal: Who did you speak to? → Formal: To whom did you speak?
Informal: Can I come in? → Formal: May I come in?
Informal: Because I was tired. → Formal: I left because I was tired.
Informal: I wanna go home. → Formal: I want to go home.
Informal: She’s smarter than him. → Formal: She is smarter than he (is).
Informal: There’s two options. → Formal: There are two options.
Informal: Not a chance. → Formal: That is not possible.
Informal: I was, like, shocked. → Formal: I was shocked.
Informal: Who are you waiting for? → Formal: For whom are you waiting?

❌ The results don’t support the hypothesis.
✅ The results do not support the hypothesis.

In essays and exam answers, always write the full form.

❌ Because the data was incomplete. The conclusion was unreliable.
✅ Because the data was incomplete, the conclusion was unreliable.

A subordinate clause cannot stand alone as a sentence in formal writing.

❌ Who did you appoint?
✅ Whom did you appoint?

Whom is the object of appoint. Use the him/her test: “You appointed him” → whom.

❌ The situation was kind of problematic.
✅ The situation was somewhat problematic.

Words like kind of, sort of, pretty much, a lot are informal. Use somewhat, rather, considerably, significantly in formal writing.

Wrong (Formal Context)	Right	Why
The results don’t show…	The results do not show…	No contractions in formal writing.
Because it was raining.	Because it was raining, we stayed home.	Fragment — attach to main clause.
Who did you choose? (formal)	Whom did you choose?	Object — use whom.
I wanna apply. (essay)	I want to apply.	Informal reduction.

Choose the formal version or spot the error.

I ___ your help. (want to / wanna)
___ I borrow your book? (Can / May)
Who did you go ___? (with / — )
Error spotting (formal): The experiment didn’t work.
Error spotting (formal): Because the sample was small.
Error spotting (formal): Who did you send the letter to?
Fill in the blank: She is better than ___ (he / him).
Fill in the blank: ___ are you waiting for? (Who / Whom)
Rewrite formally: I’m gonna apply for the job.
Choose: The data ___ support the claim. (doesn’t / does not)

want to — formal.
May — permission in formal context.
with — or rewrite: With whom did you go?
The experiment did not work. — no contractions.
Because the sample was small, the results were unreliable. — complete sentence.
To whom did you send the letter? — formal preposition fronting.
he — formal: “She is better than he (is).”
Whom — object of “waiting for.”
I am going to apply for the job. — formal.
does not — formal.

Rule: Formal grammar for exams and essays. Informal grammar for conversation. Contractions, fragments, preposition stranding, and gonna/wanna/gotta are informal. Who/whom, can/may, and full forms are formal.

Memory trick: “Exams demand formality. Conversations allow flexibility. When in doubt, go formal.”

Revise these:

I do not agree. (formal)
To whom did you write? (formal)
May I come in? (formal — permission)
I want to apply. (formal)

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