Comparative adjectives show that one person, thing, or idea has a greater or lower degree of a quality than another. They usually appear with than when two items are compared, and they belong to the larger system of Descriptive Adjectives. Their form depends on the adjective itself, so short adjectives often add er while longer adjectives usually use more. Comparative forms are essential for accurate comparison and for the later study of Superlative Adjectives.

One syllable adjectives usually form the comparative with er. If the adjective ends in a consonant vowel consonant pattern, the final consonant is doubled before er is added. Adjectives ending in y change y to i before er, especially when the y follows a consonant.

Idea	Example
One syllable adjectives usually add er.	Tall becomes taller.
A consonant vowel consonant ending doubles the final consonant.	Big becomes bigger.
A final y changes to i before er.	Happy becomes happier.

Two syllable adjectives may take er or more, depending on the word and region. Three syllable adjectives and most longer adjectives use more before the adjective. These patterns help keep comparisons natural and are part of Adjective Formation.

Idea	Example
Some two syllable adjectives can take er.	Clever becomes cleverer.
Some two syllable adjectives use more.	Clever becomes more clever.
Most three syllable adjectives use more.	Beautiful becomes more beautiful.

A small group of adjectives form comparatives without adding er or more. Good becomes better, bad becomes worse, and far may become farther or further. These forms must be learned individually because their shapes do not follow the regular patterns.

Idea	Example
Good changes to better.	She is better today.
Bad changes to worse.	The weather is worse now.
Far may become farther or further.	The station is farther away.

Comparative adjectives often stand after a linking verb and before than when the second item is expressed. In predicative position, the adjective follows verbs such as be, seem, look, or become, as in She seems happier. In attributive position, the adjective can come before a noun, as in a taller building.

Idea	Example
Comparatives are often followed by than in direct comparison.	A is taller than B.
Comparatives can follow linking verbs.	She seems happier.
Comparatives can come before a noun.	A taller building stands nearby.

Comparatives can be made stronger or weaker with modifiers such as much, far, and slightly. These words do not change the comparative form, but they show the size of the difference. Negative and alternative comparison often use not as much or less than to show a lower degree.

Idea	Example
Much can strengthen a comparative.	This road is much longer.
Slightly can weaken a comparative.	The next model is slightly better.
Less than shows a lower degree.	This task is less difficult than the last one.