Countable nouns  (also called count nouns ) are nouns that can be counted (apple, orange) and can be therefore be pluralized (apples, oranges). Uncountable nouns  (also known as non-count  or mass nouns ) are amounts of something, which we cannot count (gunpowder, rice).

Examples of countable nouns: babies, cakes, dogs, fingers, gowns, huts, ideas, lies, owls, papers, pencils, suitcases

Examples of uncountable nouns: air, ash, barley, bread, butter, dirt, flour, money, fun, gas, grass, gunpowder, ice, ink, juice, luggage, music, news, oil, pepper, rice, sand, soil, steam, sugar, vapour, water, wheat, wine

So how do we know whether a noun is countable or uncountable?

The noun is countable

if we can use the indefinite article a/an  before it.

  • I own a  car. / I play with an  ostrich.

if we can use the word many  (not much ), more , or most  to describe it.

  • She has many  friends. ( Not : She has much  friends.)

if we can express its quantity by using a number before it.

  • I have five  uncles. You have two  grandmothers.

if it takes on singular as well as plural forms.

  • an  owl / some  owls /  fifty  owls

The noun is uncountable

if a/an  is not normally used in front of it.

  • He is eating some rice . ( Not:  He is eating a rice.) Rice is an uncountable noun, so some  (which can be used for both countable and uncountable nouns) is used with it.

if the word much  can be correctly used before it.

  • How much  glue do we need? ( Not:  How many glue do we need?)

if it is not possible for us to count it. However, we can make it countable by having a quantity  for it.

  • I have just bought two cartons  or litres / liters  of milk. ( Not:  I have just bought two milk.)

if it takes only a singular form.

  • some  ice  ( Not:  some ices) / some ink  ( Not:  some inks) / some soup  ( Not:  some soups)
Nouns can be countable or uncountable. It depends on how they are used.  

Examples:

  • There are two hairs  on the snooker table. (Countable noun)
    You think my hair  looks nice? (Uncountable noun)
  • You can boil an egg . (Countable noun)
    I like to eat egg . (Uncountable noun as it refers to egg  in general, not one or two eggs.)
  • Let's stop for a coffee  on our way to the library. (Countable noun)
    She thinks she drinks too much coffee . (Uncountable noun)
  • You had a bad experience on that trip.(Countable noun)
    I have no previous experience  of this type of work. (Uncountable noun)
  • We bought a  big fish  and a roast chicken  in the supermarket. (Countable noun)
    We had some  fish  for lunch and  chicken  for dinner. (Uncountable noun)
  • As the group was large, we decided not to clink glasses . (Countable noun)
    His car windows are made of bulletproof glass . (Uncountable noun)
  • I need to press my shirt with an  iron  before we go. (Countable noun)
    The heavy chains are made of iron . (Uncountable noun)
  • We could see the bright lights  of the city from that hill. (Countable noun)
    Light  emitted by a star takes light-years to reach us. (Uncountable noun)
  • I need to press my shirt with an  iron  before we go. (Countable noun)
    The heavy chains are made of iron . (Uncountable noun)
  • He never missed the cartoon section in the papers  (newspapers) every day. (Countable noun)
    She can fold  paper  into shapes that look like dinosaurs. (Uncountable noun) 
  • I was robbed two  times  in one week. (Countable noun)
    It was a waste of precious time to watch him speak. (Uncountable noun)
  • They consider her book a  definitive work  on penguins. (Countable noun)
    We're going to have some renovation
    work  done on the house. (Uncountable noun)
Uncountable nouns include group of things
Uncountable nouns may refer to a group of things with each of the things being an individual part. They cannot be used with numbers such as a / an , one , or pluralized with +s .

Examples:

  • Mail : letters, postcards, bills, packages, parcels, etc. Â

    Not : I received a mail today.

  • Furniture : tables, chairs, beds, desks, cupboard 

    Not :The family bought a furniture yesterday.

  • Fruit : apples, oranges, bananas, mangoes and papaya 

    Not : We want to buy two (tropical)fruits today, some mangoes and a papaya. Â

  • Jewelry : rings, necklaces, earrings, bracelets, brooches Â

Countable and Uncountable Nouns are used with the following:

Countable Noun Uncountable Noun
a, an, a few, several, many, some, a little, much, some,
plenty of, a lot of, a large number of plenty of, a lot of, a large amount of, a great deal of

Refer to List 2 - Uncountable Nouns made Countable (Partitive) for more examples.