Gerunds vs Infinitives: When to Use -ing or To + Verb

One of the most confusing areas of English grammar is knowing when to use a gerund (verb + -ing) and when to use an infinitive (to + base verb). Why do we say I enjoy swimming but I want to swim? Why is I stopped smoking different from I stopped to smoke? The answer is that certain verbs, adjectives, and prepositions require a specific form, and some verbs change meaning depending on which form follows them.

A gerund looks like a verb but functions as a noun: Swimming is fun. An infinitive also functions as a noun in many cases: To swim is fun. The challenge is not understanding what they are but knowing which form to use after specific verbs. This guide gives you the rules, the key verb lists, and the practice you need to use gerunds and infinitives correctly.

How to Form / Structure

Spelling rules for gerunds:

• Most verbs: add -ing → play → playing
• Verbs ending in -e: drop the -e → make → making, write → writing
• Short verbs ending in consonant-vowel-consonant: double the final consonant → run → running, sit → sitting
• Verbs ending in -ie: change -ie to -y → die → dying, lie → lying

Three Categories of Verbs

Verbs that come before gerunds and infinitives fall into three groups:

Verbs followed by a gerund (verb + -ing):

Verbs followed by an infinitive (to + verb):

Verbs followed by either gerund or infinitive (no change in meaning):

When to Use

After Prepositions — Always Use the Gerund

When a verb follows a preposition (in, on, at, about, of, for, without, before, after, etc.), it must be in the gerund form. This is an absolute rule with no exceptions.

• She is good at cooking.
• I am interested in learning new languages.
• He left without saying goodbye.
• Thank you for helping me.
• I am tired of waiting.

As the Subject of a Sentence — Usually Gerund

When a verb form is the subject of a sentence, the gerund is far more common in everyday English:

• Swimming is great exercise.
• Reading before bed helps me relax.
• Learning a new language takes time.

The infinitive is possible but sounds more formal: To err is human.

Verbs That Change Meaning

Some verbs can take both forms, but the meaning changes significantly:

Stop:

• He stopped smoking. (He quit the habit of smoking.)
• He stopped to smoke. (He paused what he was doing in order to smoke a cigarette.)

Remember:

• I remember locking the door. (I have a memory of locking it — it happened in the past.)
• I remembered to lock the door. (I did not forget — I locked it as planned.)

Forget:

• I will never forget meeting her. (The memory of meeting her will stay with me.)
• I forgot to meet her. (I did not meet her because I forgot.)

Try:

• Try eating less sugar. (Experiment with this as a possibility.)
• Try to eat less sugar. (Make an effort to eat less sugar.)

Common Mistakes

Tricky case: "Look forward to" — Many learners think the "to" here introduces an infinitive, but it is actually a preposition. Always follow it with a gerund: I look forward to hearing from you.

Practice Examples

Choose the correct form (gerund or infinitive) for each sentence:

1. She decided _____ (study) abroad. — to study (decide + infinitive)
2. He enjoys _____ (play) the guitar. — playing (enjoy + gerund)
3. We need _____ (finish) this by Friday. — to finish (need + infinitive)
4. I cannot imagine _____ (live) without music. — living (imagine + gerund)
5. They agreed _____ (share) the cost. — to share (agree + infinitive)
6. She is interested in _____ (learn) to code. — learning (preposition + gerund)
7. He keeps _____ (forget) his password. — forgetting (keep + gerund)
8. I remembered _____ (send) the email. — sending (memory of a past action) or to send (did not forget to do it) — meaning depends on context.

Quick Reference

• Gerund (-ing form): used after certain verbs (enjoy, avoid, finish, mind, suggest, consider, practice), after all prepositions, and as the subject of a sentence.
• Infinitive (to + verb): used after certain verbs (want, need, decide, plan, hope, agree, offer, refuse, promise, learn, afford).
• Both with no change in meaning: like, love, hate, start, begin, continue.
• Both with a change in meaning: stop, remember, forget, try — learn these pairs carefully.
• After prepositions, always use the gerund. No exceptions.
• "Look forward to" takes a gerund, not an infinitive.
• When in doubt, check a learner's dictionary, which will show whether a verb takes a gerund, infinitive, or both.

The gerund vs. infinitive distinction is one of those areas where practice makes a bigger difference than memorizing rules. Read widely, notice the patterns, and keep a personal list of verbs with their correct forms. Over time, the right choice will feel natural.

Related Grammar Guides

• 50 Most Common Phrasal Verbs with Examples
• Modal Verbs: Can, Could, Should, Must — Complete Guide
• Passive Voice in English: Rules, Examples & When to Use It
• Present Continuous Tense: Rules, Structure & Examples