Here is a chart showing how to construct the superlative form in English:
One Syllable Adjectives
place 'the' before the adjective and add '-est' to end of the adjective (Note: double the final consonant if preceded by a vowel)
Example: cheap - the cheapest / hot - the hottest / high - the highest
Example Sentences
Today is the hottest day of the summer.
This book is the cheapest I can find.
Two, Three or More Syllable Adjectives
place 'the most' before the adjective
Example: interesting - the most interesting / difficult - the most difficult
Example Sentences
London is the most expensive city in England.
That is the most beautiful painting here.
Two Syllable Adjectives Ending in '-y' place 'the' before the adjective and remove the 'y' from the adjective and add 'iest'
Example: happy - the happiest / funny - the funniest
Example Sentences
New York is the noisiest city in the USA.
He is the most important person I know.
IMPORTANT EXCEPTIONS
There are some important exceptions to these rules. Here are two of the most important exceptions:
good
- good - adjective
- the best - superlative
Example Sentences
Peter is the best golf player in the school.
This is the best school in the city.
bad
- bad - adjective
- the worst - superlative
Example Sentences
Jane is the worst student in the class.
This is the worst day of my life.
Test your understanding with this short quiz.