What is an infinitive in English?

The infinitive is the base form of the verb, used without a tense or a subject of its own: to go, to be, to understand, or, without to, go, be, understand. It acts like a noun or a complement rather than the main verb of the sentence: To wait was pointless; I need to sleep; she can sing. Every verb has one, and it is the form you find in a dictionary.

What is the difference between the to-infinitive and the bare infinitive?

They are the same form with and without the marker to, and the choice depends on the word before them. Most verbs, adjectives, and nouns take the to-infinitive: I decided to stay; It's hard to explain; time to go. Modals, make, let, had better, would rather, and the verbs of perception take the bare infinitive: I must stay; They made him stay; I saw him leave.

Which verbs are followed by the infinitive?

Verbs of wanting, planning, deciding, and attempting take the to-infinitive: want, would like, need, hope, expect, plan, intend, decide, choose, agree, promise, offer, refuse, manage, learn, and afford. Some of them also take an object first: She asked me to help; They expect us to win. Verbs of enjoying, avoiding, and finishing (enjoy, avoid, mind, suggest, finish, keep) take -ing instead, so it pays to learn each verb with its pattern.

Is it wrong to split an infinitive?

No. Putting an adverb between to and the verb (to really understand, to boldly go) has been part of English for centuries and is accepted by every modern usage guide. The old prohibition came from comparing English with Latin, where the infinitive is a single word. Avoid a split only when it sounds awkward or when moving the adverb makes the sentence clearer.

What is a perfect infinitive?

It is to have plus a past participle, and it places the action of the infinitive before the time of the main verb: She seems to have left already (the leaving came before now). It is common after seem, appear, claim, and pretend, in reporting passives (He is said to have lived in Paris), and after modals, where it appears without to: You should have called. They must have forgotten.

English grammar · Intermediate

The Infinitive: To-Infinitive, Bare Infinitive, and How to Use Them

Written by Eleanor Whitfield, Lead English Curriculum Editor · Reviewed September 2026

The infinitive is the base form of a verb, either with to (to go, to be, to understand) or without it (go, be, understand). It has no tense and no subject of its own, and it does the work of a noun or a complement: it follows verbs like want and decide, adjectives like happy and difficult, and nouns like time and chance, and it explains the purpose of an action. Which form appears, to-infinitive or bare infinitive, depends on the word in front of it.

She decided to leave early.

decide is followed by the to-infinitive

What it is

Every English verb has a base form, and that form used as a verb-in-waiting is the infinitive: it names an action without pinning it to a time or a doer. The to-infinitive is the default (I hope to see you; It's easy to say). The bare infinitive appears in a fixed set of positions: after modals (can go), after make and let with an object (made me wait), after verbs of perception (saw him leave), and after a few expressions like had better and would rather. The infinitive exists because English needs a way to talk about an action as an idea, and the choice between to and no to is not about meaning but about the grammar of the word before it.

I want to go home. (to-infinitive after want) I can go home. (bare infinitive after a modal) They let me go home. (bare infinitive after let + object)

How to spot it

An infinitive is a verb in its dictionary form with no -s, -ed, or -ing. If to sits in front of a verb (to eat), it is a to-infinitive; if a modal, make, let, or a perception verb sits in front of the bare form, it is a bare infinitive. Do not confuse to the infinitive marker with to the preposition: after look forward to and be used to, a noun or -ing form follows, not a verb.

It's time to leave. (to-infinitive after a noun)
You'd better hurry. (bare infinitive after had better)
She made him apologise. (make + object + bare infinitive)
I'm looking forward to seeing you. (to as a preposition, so -ing follows: not an infinitive)

Help takes either form (help me carry it, help me to carry it), and so does dare. After know, learn, decide, and similar verbs, a question word can come first: I don't know what to say.

The Infinitive Quick Reference

Where the infinitive appears and which form it takes

Position	Form	Example
After certain verbs	to-infinitive	want, decide, hope, plan, agree, refuse: I hope to visit soon.
After verb + object	to-infinitive	want, ask, tell, advise, expect: She asked me to wait.
After adjectives	to-infinitive	happy, easy, difficult, ready: It's hard to explain.
After nouns and pronouns	to-infinitive	time, chance, way, something: I need something to read.
To express purpose	to-infinitive	I went out to get some air.
After question words	to-infinitive	know how, decide where: I don't know how to start.
After modals	bare infinitive	can, must, should, will: You must leave now.
After make, let, and perception verbs	bare infinitive	make, let, see, hear, feel + object: I saw her fall.

Common The Infinitive Examples in English

Infinitives grouped by the job they do in the sentence, since the word in front of them decides both whether they appear and which form they take:

After Verbs

We decided to take the train.: decide + to-infinitive
He refused to answer.: refuse + to-infinitive
They want us to stay for dinner.: verb + object + to-infinitive
The doctor advised her to rest.: advise + object + to-infinitive

Verbs of wanting, deciding, planning, promising, and attempting take the to-infinitive; verbs of enjoying, avoiding, and suggesting take -ing instead.

After Adjectives and Nouns

I'm glad to hear that.: adjective of feeling + to-infinitive
This form is difficult to fill in.: adjective of difficulty; the object is understood
It's a good place to work.: noun + to-infinitive describing the place
Is there anything to eat?: pronoun + to-infinitive

After adjectives, the person is introduced with for or of: It's hard for me to say. It was kind of you to come.

Purpose and Comment

I called to say thank you.: purpose: why I called
She's saving money to buy a car.: purpose with a continuous verb
To be honest, I didn't enjoy it.: comment on the whole sentence
He grew up to become a judge.: result rather than purpose

For purpose, to alone is enough: not for to buy, and not for buying when the subject of both verbs is the same person.

Bare Infinitive

You should apologise.: after a modal
My parents let me stay out late.: let + object + bare infinitive
I heard the door slam.: perception verb + object + bare infinitive
I'd rather walk than drive.: after would rather

Why not, had better, and would rather also take the bare form: Why not ask her? You'd better go.

How the Infinitive Works

Five rules decide when an infinitive appears and which form it takes, and none of them depends on meaning alone.

The Verb in Front Chooses the Form

English verbs are followed by a to-infinitive, by an -ing form, or by either, and the choice is a property of the first verb rather than a matter of sense. Want, need, decide, hope, promise, agree, refuse, manage, offer, and learn take to; enjoy, avoid, mind, suggest, finish, and keep take -ing; like, love, hate, begin, and start take both.

I want to leave. I enjoy leaving early. I like to leave early.

the first verb, not the meaning, sets the form

Learn the verb with its pattern.

To Is a Marker, Not a Preposition

The to of the infinitive has no meaning; it just introduces the verb. The preposition to (direction, or the to of look forward to, be used to, object to) is a different word and is followed by a noun or an -ing form. Confusing the two produces I'm looking forward to see you.

I used to smoke. I'm used to getting up early.

used to + infinitive is a past habit; be used to + -ing means accustomed

Infinitive to introduces a verb; preposition to introduces a noun.

Verb + Object + To-Infinitive

When one person wants, tells, asks, or allows another person to act, English puts the other person as an object before the infinitive: I want you to listen, not I want that you listen. Tell, ask, advise, allow, expect, invite, persuade, remind, and warn all use the pattern, and some, like want and expect, work with or without the object.

She reminded me to lock the door.

me is the object of remind and the doer of lock

Subject + verb + person + to + verb.

Bare After Modals, Make, Let, and the Senses

Modals take the bare infinitive (must go), and so do make and let with their object (made us wait, let them leave). Verbs of perception (see, hear, feel, watch, notice) take a bare infinitive for a complete action (I saw him cross the road) and an -ing form for one in progress (I saw him crossing). In the passive, make regains its to: We were made to wait.

Don't make me laugh. We watched the sun set.

bare infinitive after make and watch

Modal, make, let, see, hear: no to.

As a Subject, the Infinitive Usually Hides Behind It

An infinitive can be the subject of a sentence (To err is human), but modern English usually moves it to the end and puts it in front: It's dangerous to swim here rather than To swim here is dangerous. The fronted version survives in proverbs and formal writing; the it-version is the everyday one.

It's nice to meet you.

it stands in for to meet you

It + adjective + to-infinitive.

Common Mistakes with The Infinitive

Incorrect: I want that you come with us.

Correct: I want you to come with us.

Want cannot be followed by a that-clause. When the person who acts is not the subject, English puts that person as the object and follows with a to-infinitive. The same pattern applies to tell, ask, expect, and allow.

Incorrect: She made me to wait outside.

Correct: She made me wait outside.

Make and let take an object plus a bare infinitive. The to reappears only in the passive: I was made to wait outside.

Incorrect: I'm looking forward to see you.

Correct: I'm looking forward to seeing you.

Here to is a preposition, part of the phrasal verb look forward to, so it takes an -ing form. Most to before a verb is the infinitive marker, which is why this one catches so many learners.

Incorrect: He decided to don't go.

Correct: He decided not to go.

An infinitive is made negative by putting not in front of to. Don't is only for finite verbs with do-support (He doesn't go), and an infinitive has no auxiliary.

Negative, Perfect, Continuous, and Passive Infinitives

The infinitive is not a single form. It has a negative, and it combines with have, be, and the past participle to show time and voice.

The negative infinitive: not to

Not goes directly before to. Placing it after to (to not go) is common in speech and accepted by most editors, but not to is the standard order and the safer choice.

She decided not to apply.: not before to
Try not to be late.: the negative belongs to the infinitive, not to try
He told me not to worry.: verb + object + negative infinitive

Compare I didn't decide to apply (no decision was made) with I decided not to apply (a decision was made): the position of not changes the meaning.

The perfect infinitive: to have + participle

To have plus a past participle shows that the action of the infinitive happened before the time of the main verb. It is common after seem, appear, claim, pretend, and be said, and after modals to look back at the past.

She seems to have forgotten our meeting.: the forgetting came before now
He claims to have met the president.: an earlier event reported now
You should have asked first.: bare perfect infinitive after a modal

I'd like to have seen it means I regret missing it; I'd have liked to see it says the same thing with the perfect on the main verb.

Continuous and passive infinitives

To be + -ing describes an action in progress; to be + past participle turns the infinitive passive. Both follow the same rules as the plain to-infinitive.

She seems to be enjoying the course.: continuous: in progress now
There's a lot of work to be done.: passive: the work will be done by someone
He hopes to be chosen for the team.: passive after hope

Nobody likes to be told what to do stacks a passive infinitive (to be told) and a plain one after a question word (what to do).

Quick Check: The Infinitive

Put the verb in brackets into the right form: to-infinitive, bare infinitive, or -ing.

1. We hope ___ (move) house before the summer.

Answer: to move

hope + to-infinitive

2. My boss let me ___ (leave) early on Friday.

Answer: leave

let + object + bare infinitive

3. I'm not used to ___ (drive) on the left.

Answer: driving

be used to + -ing: to is a preposition here

4. She told us ___ (not / touch) anything.

Answer: not to touch

negative infinitive: not before to

5. He seems ___ (lose) weight since I last saw him.

Answer: to have lost

perfect infinitive: the losing happened before now

6. It's important ___ (arrive) on time.

Answer: to arrive

it + adjective + to-infinitive

The Infinitive FAQs

What is an infinitive in English?: The infinitive is the base form of the verb, used without a tense or a subject of its own: to go, to be, to understand, or, without to, go, be, understand. It acts like a noun or a complement rather than the main verb of the sentence: To wait was pointless; I need to sleep; she can sing. Every verb has one, and it is the form you find in a dictionary.
What is the difference between the to-infinitive and the bare infinitive?: They are the same form with and without the marker to, and the choice depends on the word before them. Most verbs, adjectives, and nouns take the to-infinitive: I decided to stay; It's hard to explain; time to go. Modals, make, let, had better, would rather, and the verbs of perception take the bare infinitive: I must stay; They made him stay; I saw him leave.
Which verbs are followed by the infinitive?: Verbs of wanting, planning, deciding, and attempting take the to-infinitive: want, would like, need, hope, expect, plan, intend, decide, choose, agree, promise, offer, refuse, manage, learn, and afford. Some of them also take an object first: She asked me to help; They expect us to win. Verbs of enjoying, avoiding, and finishing (enjoy, avoid, mind, suggest, finish, keep) take -ing instead, so it pays to learn each verb with its pattern.
Is it wrong to split an infinitive?: No. Putting an adverb between to and the verb (to really understand, to boldly go) has been part of English for centuries and is accepted by every modern usage guide. The old prohibition came from comparing English with Latin, where the infinitive is a single word. Avoid a split only when it sounds awkward or when moving the adverb makes the sentence clearer.
What is a perfect infinitive?: It is to have plus a past participle, and it places the action of the infinitive before the time of the main verb: She seems to have left already (the leaving came before now). It is common after seem, appear, claim, and pretend, in reporting passives (He is said to have lived in Paris), and after modals, where it appears without to: You should have called. They must have forgotten.