Adverbs, like adjectives, have three degrees of comparison: positive, comparative and superlative which are formed in different ways:

• adverbs having just one syllable such as clean, high, low, etc. form the comparative and superlative the same way short adjectives do – adding -er (comparative) and –est (superlative) to the positive form.

eg. clean – cleaner – the cleanest

• adverbs that end in –ly take more (for comparative) and most (for superlative).

eg. happily – more happily – the most happily

The exception in this category is the adverb early (early – earlier – earliest).

 

Some adverbs are irregular, which means they change their form for comparative and superlative.

much – more – most

badly – worse – worst

well – better – best

little – less – least