What is the difference between interested and interesting?

Interested describes a person's feeling: Laila was interested in the star map. Interesting describes the thing that causes that feeling: The star map was interesting. The same split applies to bored/boring, tired/tiring, and the rest of the feeling pairs. Ask who feels it, and what causes it.

Why is I am boring a problem?

Because boring describes a cause. I am boring means you make other people feel bored. If you mean you feel boredom, say I am bored. English speakers hear I am boring as a claim about your personality, so the ending matters socially as well as grammatically.

Are these words tenses or adjectives?

On this page they are adjectives. Laila was fascinated is be plus an adjective of state, like Laila was tired. You can put very in front of them (very interested, very boring), which you cannot do with a normal past tense. The same spelling is a past participle in other sentences (The meteor shower fascinated Laila), but the feeling/cause pair is adjectival.

Can a person take the -ing form?

Yes, when that person is the cause of the feeling: The guide was interesting means the guide held our attention, and Oskar is boring when he reads the whole script means he causes boredom. When the person is the one who feels it, use -ed (The guide was interested; Oskar is bored).

How do I remember which ending to use?

Point at the noun you are describing: if it has feelings, use -ed (a bored child, We were surprised), and if it produces feelings in someone else, use -ing (a boring introduction, a fascinating show). For a check, add by: Laila was fascinated by the shower, which you cannot reverse as the shower was fascinated by Laila.

English grammar · Beginner

-ed and -ing Adjectives: Interested vs. Interesting

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

Pairs like interested/interesting, bored/boring, and fascinated/fascinating are adjectives, not tenses. The -ed form describes a person's feeling (Laila was fascinated). The -ing form describes the person, thing, or event that causes the feeling (the show was fascinating). Mix them up and you say something unintended: I am boring means I cause boredom in other people, not that I feel bored.

Laila was fascinated by the meteor shower, and the planetarium show itself was fascinating.

-ed for her feeling, -ing for the thing that caused it

What it is

English builds two adjectives from many emotion verbs. The -ed adjective points at the person who feels something: interested, bored, tired, surprised, frightened, fascinated. The -ing adjective points at whatever produces that feeling: interesting, boring, tiring, surprising, frightening, fascinating. The ending is not a tense marker here. Laila was fascinated is an adjective after be, not the past of fascinate in a story. The planetarium show is fascinating describes the show, not something the show is doing right now.

The meteor talk bored the children. (verb) The children were bored. ( -ed adjective: their feeling) The meteor talk was boring. ( -ing adjective: the cause)

How to spot it

If the word describes a person's inner state, it almost always ends in -ed. If it describes a film, a lesson, a job, a person as a cause, or a situation, it almost always ends in -ing. Ask who feels it and what causes it, then pick the ending.

Laila was interested in the star map. (interested: her feeling)
The star map was interesting. (interesting: the map caused the feeling)
Oskar felt tired after the late showing. (tired: his feeling after the cause)
The late showing was tiring. (tiring: the showing caused the tiredness)

A few -ed adjectives do not describe feelings at all (a locked door, a broken projector). Those are past participles used as adjectives of state. This page is about the feeling pairs: bored/boring, interested/interesting, and their relatives.

-ed and -ing Adjectives Quick Reference

Feeling vs. cause

-ed (the feeling)	-ing (the cause)	Example pair
interested	interesting	She was interested. The star map was interesting.
bored	boring	The children were bored. The talk was boring.
excited	exciting	Oskar was excited. The meteor shower was exciting.
tired	tiring	Laila felt tired. The late showing was tiring.
surprised	surprising	We were surprised. The result was surprising.
frightened	frightening	He was frightened. The dark dome was frightening.
fascinated	fascinating	She was fascinated. The show was fascinating.
annoyed	annoying	I was annoyed. The tannoy was annoying.

Common -ed and -ing Adjectives Examples in English

The same planetarium visit, grouped by whether the adjective names a feeling or a cause:

Feelings (-ed)

Laila was fascinated by the meteor shower.: fascinated: her inner state
The children were bored during the long introduction.: bored: how they felt
Oskar felt tired after the late showing.: tired: a feeling, not a cause
We were surprised by the quiet in the dome.: surprised: our reaction

The subject of an -ed feeling adjective is almost always a person or an animal. Things do not feel bored or interested.

Causes (-ing)

The planetarium show was fascinating.: fascinating: the show caused the feeling
The long introduction was boring.: boring: it caused boredom
The late showing was tiring.: tiring: it caused tiredness
The dark walk back to the tram was frightening.: frightening: it caused fear

The subject of an -ing adjective in this pair is the film, the job, the walk, the person who causes the feeling. I am boring describes your effect on other people.

People as Cause or as Feeler

The guide was interesting about the meteor paths.: the guide caused interest
The guide was interested in meteor paths.: the guide felt interest
Oskar is boring when he reads the whole script.: he causes boredom in the room
Oskar is bored when he has to read the whole script.: he feels boredom

A person can take either ending. The -ed form is how they feel. The -ing form is the effect they have on others. This is the pair learners most often reverse.

Before a Noun

a fascinating meteor shower: -ing before a noun that causes the feeling
a bored child in the front row: -ed before a person who feels it
an interesting star map: the map causes interest
an excited crowd under the dome: the crowd feels excitement

The same rule applies in front of a noun. A boring film causes boredom. A bored audience feels it.

How -ed and -ing Adjectives Work

One question decides the ending: who feels it, and what causes it.

-ed Describes the Person Who Feels

Interested, bored, tired, surprised, frightened, and fascinated are adjectives of inner state. They usually follow be, feel, look, or seem, and their subject is a person: Laila was fascinated. Oskar felt tired. They can also sit in front of a person-noun: a bored child, an excited crowd. They are not past tenses in these sentences, even though they look like past participles.

Laila was interested in the star map. She looked surprised.

both -ed forms describe her state

-ed = the person feels it.

-ing Describes the Cause

Interesting, boring, tiring, surprising, frightening, and fascinating describe the thing (or person) that produces the feeling. The subject is often not a person: The show was fascinating. The introduction was boring. When the subject is a person, you are saying they have that effect on other people: The guide was interesting. I am boring.

The planetarium show was fascinating. The long introduction was boring.

the show and the introduction are causes, so -ing

-ing = this thing causes the feeling.

By Names the Cause After an -ed Adjective

After a feeling adjective you can add by plus the cause: Laila was fascinated by the meteor shower. We were surprised by the quiet. That by-phrase is optional. It is also why the -ed form looks like a passive (was fascinated by). Treat it as an adjective: very fascinated, quite bored, and look fascinated all work like other adjectives.

The children were bored by the long introduction.

bored is the feeling; by names the cause

Be + -ed + by + cause.

Very and Other Intensifiers Follow Adjective Rules

Because these words are adjectives, they take adjective modifiers: very interesting, quite boring, really tired, absolutely fascinating. Some of the -ing forms sit at the strong end of a scale (fascinating, exhausting, terrifying) and pair more naturally with absolutely than with very. That overlap belongs with extreme adjectives; the ending rule on this page does not change.

The show was really interesting. Laila was absolutely fascinated.

really with a gradable -ing form; absolutely with a strong -ed form

They are adjectives, so they take adjective modifiers.

Common Mistakes with -ed and -ing Adjectives

Incorrect: I am very boring in this planetarium show.

Correct: I am very bored in this planetarium show.

I am boring means you cause boredom in other people. If you want to talk about your own feeling during the show, the adjective is bored. This reversal is the classic -ed/-ing error.

Incorrect: The meteor shower was fascinated.

Correct: The meteor shower was fascinating. / Laila was fascinated by the meteor shower.

A shower cannot feel fascination. The -ed form needs a person as subject. For the shower as cause, use fascinating. For Laila's feeling, use she was fascinated.

Incorrect: The children were boring during the long introduction.

Correct: The children were bored during the long introduction.

Were boring would mean the children caused boredom in someone else. The intended meaning is their inner state during a dull talk, which is bored.

Incorrect: It was a bored show.

Correct: It was a boring show.

Before a noun that is the cause (a show, a film, a job), the adjective is -ing. Bored show would describe a show that feels boredom, which is not possible.

Other Common -ed / -ing Pairs

The same feeling-vs-cause rule covers a longer list than interested and bored.

The core classroom set

These pairs follow the rule with no extra meaning change.

confused / confusing: feeling vs cause: confused vs confusing
embarrassed / embarrassing: feeling vs cause: embarrassed vs embarrassing
disappointed / disappointing: feeling vs cause: disappointed vs disappointing
relaxed / relaxing: feeling vs cause: relaxed vs relaxing

If you know the verb (confuse, embarrass, disappoint, relax), you can build both adjectives and apply the feeling/cause test.

Stronger feeling pairs

A few pairs sit at the top of a scale and often take absolutely rather than very.

exhausted / exhausting: feeling vs cause: exhausted vs exhausting
amazed / amazing: feeling vs cause: amazed vs amazing
terrified / terrifying: feeling vs cause: terrified vs terrifying

Amazing and exhausting still describe the cause. Amazed and exhausted still describe the person. The ending rule does not change at the strong end of the scale.

Not every -ed word is a feeling

Locked, broken, closed, and finished are adjectives of state, not of emotion. They have no feeling/-ing pair of this kind.

The projector is broken.: a state, not a feeling
a locked side door: -ed as a result state
The dome stayed closed until dusk.: closed describes a state of the dome

You cannot say the projector is breaking to mean the same as broken, and there is no I am broken/breaking feeling pair here. Keep this set separate from bored/boring.

Quick Check: -ed and -ing Adjectives

Choose the -ed or -ing form.

1. Laila was ___ by the meteor shower. (fascinate)

Answer: fascinated

her feeling, so -ed

2. The planetarium show was ___. (fascinate)

Answer: fascinating

the show is the cause, so -ing

3. The children were ___ during the long introduction. (bore)

Answer: bored

their feeling

4. I am not ___; I am just quiet. (bore, meaning 'I do not cause boredom')

Answer: boring

a person as cause: -ing

5. The late showing was ___ , and Oskar felt ___. (tire / tire)

Answer: tiring, tired

cause then feeling

-ed and -ing Adjectives FAQs

What is the difference between interested and interesting?: Interested describes a person's feeling: Laila was interested in the star map. Interesting describes the thing that causes that feeling: The star map was interesting. The same split applies to bored/boring, tired/tiring, and the rest of the feeling pairs. Ask who feels it, and what causes it.
Why is I am boring a problem?: Because boring describes a cause. I am boring means you make other people feel bored. If you mean you feel boredom, say I am bored. English speakers hear I am boring as a claim about your personality, so the ending matters socially as well as grammatically.
Are these words tenses or adjectives?: On this page they are adjectives. Laila was fascinated is be plus an adjective of state, like Laila was tired. You can put very in front of them (very interested, very boring), which you cannot do with a normal past tense. The same spelling is a past participle in other sentences (The meteor shower fascinated Laila), but the feeling/cause pair is adjectival.
Can a person take the -ing form?: Yes, when that person is the cause of the feeling: The guide was interesting means the guide held our attention, and Oskar is boring when he reads the whole script means he causes boredom. When the person is the one who feels it, use -ed (The guide was interested; Oskar is bored).
How do I remember which ending to use?: Point at the noun you are describing: if it has feelings, use -ed (a bored child, We were surprised), and if it produces feelings in someone else, use -ing (a boring introduction, a fascinating show). For a check, add by: Laila was fascinated by the shower, which you cannot reverse as the shower was fascinated by Laila.