An adjective is a describing word: 'big,' 'happy,' 'expensive.' A comparative adjective compares two things — it says one is more than the other: 'Chicago is bigger than Miami.' A superlative adjective compares one thing with a whole group — it says this one is number one of all: 'Chicago is the biggest city in this state.' Short adjectives add -er and -est ('big → bigger → biggest'); long adjectives use the words more and most ('more expensive,' 'the most expensive').
2. Detailed explanation
Start from zero. An adjective is a describing word: big, small, happy, expensive. When we compare two things side by side, English changes the adjective into a form called the comparative: 'bigger,' 'happier,' 'more expensive.' The comparative is about TWO things: 'My car is faster than your car.' When we compare one thing with a whole group and say it is number one, English uses another form called the superlative: 'the fastest,' 'the happiest,' 'the most expensive.' The superlative almost always carries the word 'the' in front: 'He is the tallest student in the class.'
How do you build these forms? A syllable is one sound beat in a word: 'big' has one, 'happy' has two, 'expensive' has three. For short adjectives of one syllable, add -er for the comparative and -est for the superlative: tall → taller → the tallest. Watch two spelling rules: if a short adjective ends with one vowel + one consonant, double the consonant — big → bigger, hot → hotter. If an adjective ends in -y, change the y to i — happy → happier, easy → the easiest; this covers short adjectives and two-syllable adjectives ending in -y. Longer adjectives do not take endings; they use more and most: more beautiful, the most beautiful; more expensive, the most expensive. Three adjectives are completely irregular and change their whole shape: good → better → the best; bad → worse → the worst; far → farther → the farthest.
Now the partner words. A comparative is not finished without 'than' — than is the word that introduces the second thing: 'She is older than me.' Never use 'that' or 'from' here. A superlative is not finished without 'the' and, usually, the group: 'the biggest city in Texas,' 'the best day of my life.' English also has an equal comparison: 'as + adjective + as' means 'exactly the same': 'He is as tall as his brother.' Its negative, 'not as tall as,' means 'less tall.' In the opposite direction, long adjectives can use less and the least ('less expensive,' 'the least expensive'); with short adjectives, English prefers 'not as…as.'
Take two sentences apart, word by word. 'My house is bigger than yours': My house (thing number one) + is + bigger (the comparative of big, with the doubled g) + than (the comparison word) + yours (your house — thing number two). 'She is the best student in the class': She + is + the (the word that always stands before a superlative) + best (the superlative of good — an irregular form) + student + in the class (the group she is number one in).
Remember this first: memorize three things. One: short adjective → add -er and -est; long adjective → more and most; and good, bad, far change completely: better, worse, farther. Two: a comparative takes 'than,' a superlative takes 'the.' Three: use only one comparison marker at a time — never 'more bigger,' never 'the most biggest.'
3. Formula / structure
Step by step — how to build a sentence:
Comparative: 1) Start with thing number one (My car). 2) Add is/are. 3) Build the comparative: short adjective + -er (faster) OR more + long adjective. 4) Add 'than' + thing number two. Result: 'My car is faster than your car.' Superlative: 1) Start with the winner (She). 2) Add is. 3) Add 'the' + short adjective + -est (the tallest) OR 'the most' + long adjective. 4) Add the group (in the class). Result: 'She is the tallest in the class.' Question: 1) Put the verb first (Is). 2) Add thing number one. 3) Add the comparative form. 4) Add 'than' + thing number two + '?'. Result: 'Is your car faster than mine?'
comparative — long adjectives:
more + adjective + than → 'more expensive than,' 'more interesting than'
comparative — short adjectives:
adjective + er + than → tall → 'taller than' · big → 'bigger than' (double the last consonant: big–bigger, hot–hotter) · happy → 'happier than' (change y to i)
equal comparison:
as + adjective + as → 'as tall as' (exactly the same) · not as + adjective + as → 'not as tall as' (less) · less + long adjective + than → 'less expensive than'
irregular:
good → better → the best · bad → worse → the worst · far → farther → the farthest
superlative — long adjectives:
the most + adjective → 'the most expensive,' 'the most beautiful'
superlative — short adjectives:
the + adjective + est → 'the tallest,' 'the biggest' (double the consonant), 'the happiest' (change y to i)
4. When to use it
Comparing cities, weather, and places: 'New York is bigger than Boston.' 'Today is colder than yesterday.'
Shopping and prices: 'This phone is cheaper than that one.' 'Which coffee is the most expensive?'
Talking about people: 'My sister is taller than me.' 'He is the youngest in his family.'
Giving opinions and recommendations: 'This is the best restaurant in town.'
Sports and records: 'She is the fastest runner on the team.'
Describing change: 'The days are getting longer.' 'Your English is better than last month.'
5. When NOT to use it
Don't use 'than' with a superlative: ✗ 'He is the tallest than me' → ✓ 'He is taller than me' or 'He is the tallest in the class.'
Don't compare twice: ✗ 'more bigger,' ✗ 'the most easiest' → choose one marker: -er/-est OR more/most.
Don't drop 'the' before a superlative: ✗ 'She is best student' → ✓ 'She is the best student.'
Don't add -er or -est to a long adjective: ✗ 'expensiver,' 'beautifullest' → ✓ 'more expensive,' 'the most beautiful.'
Don't replace 'than' with 'that': ✗ 'bigger that me' → ✓ 'bigger than me.'
6. Positive examples
My brother is taller than me.
This exercise is easier than the last one.
Tokyo is bigger than Osaka.
She is the youngest person in the office.
This is the most interesting book in the library.
Your car is faster than mine.
Today is hotter than yesterday.
He is the best player on the team.
This hotel is cheaper than that one.
Maria is as friendly as her sister.
It was the worst day of the year.
English grammar is easier than I expected.
7. Negative examples
This phone is not as expensive as that one.
He isn't taller than his father.
This test wasn't easier than the last one.
She is not the oldest child in the family.
The soup is not as hot as I like it.
My new shoes aren't more comfortable than my old ones.
8. Questions
Which city is bigger, Chicago or Houston?
Is a train faster than a bus?
Who is the tallest student in your class?
Which phone is cheaper?
Is this the best way to the airport?
Is your new apartment bigger than your old one?
9. Short answers
Yes, it is. (Is this hotel cheaper than that one?)
No, it isn't — mine is older. (Is your car newer?)
Chicago is. (Which city is bigger?)
Maria is. (Who is the tallest?)
The blue one. (Which bag is cheaper?)
10. Common mistakes
✗ My car is more faster than yours✓ My car is faster than yours.Why: 'fast' is a short adjective, so it takes -er. Using 'more' AND '-er' compares twice — English allows only one comparison marker.
✗ She is the most happiest girl in the class✓ She is the happiest girl in the class.Why: 'happy' becomes 'happiest' with -est, so adding 'most' compares twice. And remember the spelling: change y to i — happiest, not happyest.
✗ This book is better that that one✓ This book is better than that one.Why: comparisons use the word 'than.' 'Than' and 'that' look similar, but 'that' is always wrong in a comparison.
✗ He is taller his brother✓ He is taller than his brother.Why: a comparative is unfinished without 'than' plus the second thing you compare with. 'Taller' always asks: taller than what?
✗ Tokyo is the bigger city in Japan✓ Tokyo is the biggest city in Japan.Why: comparing one thing with a whole group needs the superlative 'biggest,' and a superlative needs 'the' in front of it.
✗ This is the expensivest hotel in town✓ This is the most expensive hotel in town.Why: 'expensive' is a long adjective — three syllables — so it never takes -est. Long adjectives use 'the most.'
✗ I am more good at soccer than him✓ I am better at soccer than him.Why: 'good' is irregular — its comparative is the completely different word 'better.' There is no 'gooder' and no 'more good.'
11. American English notes
🇺🇸 American English
Americans compare things constantly in everyday speech: prices ('Gas is cheaper here'), weather ('It's hotter than yesterday'), sports ('the best team in the league'). In casual American English you will hear comparatives standing alone, with the second part understood: 'Do you want the bigger one?' You will also hear superlatives without 'the' after words like my and her: 'my best friend,' 'her worst day.' One spelling point to lock in: adjectives ending in -y always change to -ier and -iest in American writing (happier, prettier, easier) — never 'happy-er.' For distance, 'farther' is the common American choice for real, physical distance ('Chicago is farther than I thought'); 'further' is used more for abstract ideas ('further information').
12. Similar grammar — comparison
Compare
Learners confuse the comparative and the superlative because both change the adjective — keep their jobs separate. A comparative belongs to exactly TWO things and almost always travels with the word 'than': 'bigger than…' A superlative names ONE winner inside a group and travels with the word 'the': 'the biggest in the class.' Rule of thumb: if you see 'than,' the form must be a comparative; if you see 'the' plus a group (in the world, of all my friends, in Texas), the form must be a superlative. Also compare the equal form 'as tall as' — the adjective does not change at all, and the meaning is 'exactly the same,' which is a different job from -er. Finally, never stack two markers: 'more' already compares, so 'more bigger' says the same thing twice.
13. Natural spoken English
'This one is way cheaper.' (Americans use 'way' before a comparative to mean 'much.')
'It's the best pizza in town, honestly.'
'My new job is so much better than my old one.'
'Which one is closer — the bank or the post office?'
'He's getting taller every month.'
'That was the worst traffic I've ever seen.'
14. Real-life examples
Shopping: 'Do you have this shirt in a bigger size?'
Comparing prices online: 'This hotel is $20 cheaper per night than the other one.'
Weather apps: 'Tomorrow will be colder and windier than today.'
Sports news: 'She is the fastest woman in the world this year.'
Restaurant reviews: 'Great food, but the other place is quieter and cheaper.'
At work: 'This plan is more realistic than the first one.'
15. Mini dialogue
AI want a new laptop. This one is cheaper than that one.
BTrue, but that one is faster and lighter.
AWhich one is the best for schoolwork?
BFor schoolwork, the cheaper one is fine. It's as fast as you need.
AIs the screen bigger on the expensive one?
BYes, it has the biggest screen of the three. But it's also the heaviest!
AHmm. Then the middle one is better for me — lighter, and not as expensive.
BGood choice. It's the most popular model in the store.
16. Summary
Comparatives (two things, + than) use -er for short adjectives and more for long ones; superlatives (one winner in a group, + the) use -est and most; good/better/best, bad/worse/worst and far/farther/farthest are irregular, and as…as compares equals.
17. Practice exercises
Warm up with the first questions, then take the full quiz — every answer has a detailed explanation (parts 19–20 of this lesson: answer key + explanations live inside the quiz feedback).
18. The full quiz
50 questions, mixed formats, in difficulty order: easy → medium → intermediate → challenging → advanced.