Difference Between Less and Fewer

When do we use Less ?

• Less is used when talking about things that are uncountable or have no plural.
  
• It is compatible with collective nouns, non-countable nouns and volumes.
• Examples

1. I earn less money than a policeman.
2. Many of us maybe eat less sugar.
3. I sleep less than my father.

When do we use Fewer ?

• Fewer is used when talking about things or people in the plural.
• It is used countable nouns and individual items.
• Examples
  

1. I bought fewer books this year.
2. They’ve got fewer problems than they used to have.
3. Now I’ve got fewer tasks than I used to have.