The comparative of an adjective or adverb describes a comparison of one person or thing with another person or thing. Most comparatives require an -er ending, for example, taller, shallower. If the adjective or adverb ends in a single consonant, that consonant is doubled before adding the ending: mad → madder. If an adjective or adverb ends in -y, change it to -i then add -er: funny → funnier.
The superlative of an adjective or adverb shows the greatest degree of the meaning of the adjective or adverb. Most superlatives end in -est: tallest, shallowest. If the adjective or adverb ends in a single consonant, that consonant is doubled before adding the ending: mad → maddest. If an adjective or adverb ends in -y, change it to -i then add -est: funny → funniest.
Both the comparative and the superlative are formed in another way by using more or most. The word more is placed in front of the adjective or adverb to form the comparative, and the word most is placed in front of the adjective or adverb to form the superlative: more interesting/most interesting, more logical/most logical. This formation is used primarily with words that are of two syllables or more and that come to English from French, Latin, or other foreign sources.
The other formation (long, longer, longest) is Anglo-Saxon in origin. Compare these lists of comparatives and superlatives:
| Anglo-Saxon Origin | Anglo-Saxon Origin | Foreign Origin | Foreign Origin |
| bigger | biggest | more critical | most critical |
| finer | finest | more dangerous | most dangerous |
| grander | grandest | more dynamic | most dynamic |
| happier | happiest | more fruitful | most fruitful |
| jollier | jolliest | more harmonious | most harmonious |
| kinder | kindest | more hopeless | most hopeless |
| mightier | mightiest | more intense | most intense |
| poorer | poorest | more sensitive | most sensitive |
| smaller | smallest | more visible | most visible |
| thinner | thinnest | more willing | most willing |
Note that words that end in -ful, -less, and -ing use more and most to form the comparative and superlative, even though such words do not have a foreign language origin.
There are a few irregular formations that must simply be memorized:
| Positive | Comparative | Superlative |
| bad | worse | worst |
| far | farther/further | farthest/furthest |
| good | better | best |
| little (amount) | less | least |
| many | more | most |
| much | more | most |
| well | better | best |
It is possible to use a comparative in a sentence without mentioning the person or thing with which another person or thing is being compared. Look at these examples:
- Jorge is a lot taller.
- My sister was thinner a few years ago.
In such sentences the person or thing compared is assumed. When stating the person or thing with which another person or thing is being compared, use the word than:
- Jorge is a lot taller than Michelle.
- My sister was thinner a few years ago than she is now.
The formation of both adjectives and adverbs in the comparative is identical. The difference is how they are used in a sentence:
- My car is faster than your car. (adjective)
- She runs faster than you do. (adverb)
With adverbs that end in -ly, both forms of comparative and superlative are possible:
- He spoke quicker./He spoke more quickly.
- He spoke the quickest./He spoke the most quickly.
The superlative adjective or adverb frequently is preceded by the word the:
- Lars is the strongest boy.
- She is the most beautiful girl here.
When the superlative is a predicative adjective and not followed by a noun, the word the can be omitted:
- Lars is strongest when he’s not tired.
- She is most beautiful when she wakes up in the morning.
Comparative and superlative adverbs that are formed with more and most require the adverbial ending -ly:
- more willingly
- most capably