In English, some nouns are countable, meaning you can count them as separate items: one book, two books. Other nouns are uncountable, meaning they are seen as a mass, substance, or idea and are not normally counted: water, rice, information. Countability affects which determiners you can use, whether a noun can be plural, and how you ask about quantity.

Countable nouns refer to individual people, animals, things, or units that can be separated and counted. They have a singular and a plural form, and they can be used with numbers. With singular countable nouns, you normally need an article or another determiner: a car, the car, my car.

Uncountable nouns refer to substances, materials, categories, activities, or abstract ideas viewed as a whole rather than separate units. They usually do not have a plural form and are not used directly with numbers. They often appear without an article when speaking generally: Sugar is sweet; Information is useful.

Countability determines which quantifiers and determiners are grammatical. Use a, an, and many with countable nouns, and use much with uncountable nouns. Some determiners work for both, but the meaning may shift depending on whether you mean separate items or a general amount.

Rule	Example
Use a or an with singular countable nouns	I saw a dog.
Use many with countable plural nouns	Many students are absent.
Use much with uncountable nouns	We do not have much time.
Use some and any with both types	We need some chairs and some water.
Use a lot of with both types in neutral style	She has a lot of friends and a lot of patience.

Countable nouns regularly pluralize to show more than one item, while uncountable nouns normally stay in a singular form even when the amount is large. Verbs usually agree with the grammatical form: plural verbs with plural countables, and singular verbs with uncountables. When an uncountable noun is treated as a type or variety, it can sometimes be plural.

Rule	Example
Countable plurals take plural verbs	These apples are fresh.
Uncountables usually take singular verbs	This furniture is expensive.
Uncountables can be plural when meaning types or varieties	The store sells many teas.

To count uncountable nouns, English uses containers, measures, and portions called measure words. You say a piece of, a bottle of, a cup of, or a kilo of plus the uncountable noun. This allows numbers and plural forms to attach to the measure word, not the uncountable noun itself.

Rule	Example
Use a piece of for single portions of an uncountable item	I need a piece of advice.
Use a container word to count liquids and items sold in containers	Two bottles of water, please.
Use measurement units for weight and quantity	Three kilos of rice.
Use a slice of for flat food portions	She ate two slices of bread.
Use an item of for formal counting of abstract or grouped nouns	An item of information was missing.

Many everyday nouns are typically uncountable in English even if they are countable in other languages. These often include information, advice, furniture, equipment, homework, luggage, and traffic. Learning these as uncountable helps you choose correct determiners and avoid incorrect plurals.

Word/Phrase	Definition	Example
information	facts or knowledge	This information is helpful.
advice	guidance or suggestions	I need some advice.
furniture	household items like tables and chairs	The furniture is new.
equipment	tools or machines used for a purpose	The equipment is expensive.
homework	school tasks to do at home	I have a lot of homework.
luggage	bags and suitcases for travel	Our luggage is heavy.
traffic	vehicles on roads as a mass	Traffic is terrible today.

Some nouns can be countable or uncountable depending on meaning. When uncountable, they usually refer to a substance, general activity, or abstract idea; when countable, they refer to a unit, a type, or an instance. The grammar around the noun changes with the meaning you choose.

Word/Phrase	Definition	Example
coffee	uncountable: the drink in general	I do not drink coffee.
a coffee	countable: one serving	Can I get a coffee?
chicken	uncountable: the meat	We ate chicken for dinner.
a chicken	countable: the animal	A chicken is in the yard.
paper	uncountable: material for writing and printing	I need more paper.
a paper	countable: a document or newspaper	She wrote a paper.
experience	uncountable: life knowledge over time	He has a lot of experience.
an experience	countable: one event that happened to you	That was an amazing experience.

English uses different question forms to ask about quantities depending on countability. Use how many for countable plural nouns and how much for uncountable nouns. In answers, you can use numbers with countables and measures or general quantity words with uncountables.

Rule	Example
Use how many with countable plural nouns	How many tickets do we need?
Use how much with uncountable nouns	How much sugar is in this?
Answer countables with numbers	We need three tickets.
Answer uncountables with measures or quantity expressions	We need a little sugar or two spoons of sugar.

Articles and reference interact with countability. Singular countable nouns usually cannot stand alone when you speak generally, so you use a or the or another determiner. Uncountable nouns often appear with zero article for general meaning, but take the when you mean a specific, known amount or context.

Rule	Example
Singular countables usually need a determiner	I bought a jacket.
Zero article with uncountables for general statements	Milk is good for you.
Use the with uncountables for a specific situation	The milk in the fridge is sour.
Use the with countables for specific reference	The jacket I bought is too big.