The quick answer

Use a comparative to compare two things: taller, bigger, more expensive, usually followed by than. Use a superlative to put one thing above all the others: the tallest, the biggest, the most expensive.

The rule

The form depends on how long the adjective is. Short adjectives of one syllable add -er and -est: tall, taller, the tallest. Long adjectives of three syllables or more take more and most: expensive, more expensive, the most expensive. Two-syllable adjectives ending in -y change the y to i: happy, happier, the happiest.

Comparatives are normally followed by than. Superlatives almost always take the in front of them. A few very common words do not follow the pattern at all: good, better, the best and bad, worse, the worst.

Form

Examples

• My brother is taller than me.
• This bag is bigger than that one.
• Today is hotter than yesterday.
• She is the happiest person in our class.
• That was the most expensive meal of the trip.
• This film is better than the first one.

Common mistakes

• ❌ My brother is more tall than me. → ✅ My brother is taller than me. Short adjectives take -er, not more.
• ❌ It is the most big room. → ✅ It is the biggest room. Short adjectives take -est, not most.
• ❌ She is taller that me. → ✅ She is taller than me. Comparisons use than, not that.
• ❌ He is best student here. → ✅ He is the best student here. A superlative needs the in front.