AMOUNT -NUMBER -QUANTITY
The difference between 'amount', 'number' and 'quantity'

The words 'amount', 'number' and 'quantity' are often confused or misused in English.
-'Amount' is used with inanimate (non-living) things that cannot be counted.
-'Number' is used for things, both animate and inanimate, that can be counted.
-'Quantity' is a measure of both countable and uncountable things that are usually inanimate.

• AMOUNT
  We use ‘amount’ with uncountable inanimate things, for example:
  -An amount of money/paper/oil/flour/butter...
  -An amount of respect/indifference/care/ attention/work/time...
   NOT : an amount of people
  • The job took a certain amount of time.
  • A huge amount of paint was used.
  • The renovation will require a large amount of work.
  • The historical project required an inordinate amount of research.
  • We owe him a certain amount of respect.
  • No amount of care will cure the patient.
    
    
• NUMBER
  We use ‘number’ with countable things, animate or inanimate:
  • We have a number of things to discuss.
  • A great number of people turned up.
  • A huge number of meals were served.
  • A small number of items were broken.
  • The brochure contains a number of errors.
  • A large number of students participated in the project.
  • The virus affected a large number of animals.
    
    
• QUANTITY
  We use ‘quantity’ (or ‘quantities’) with both countable and uncountable things that are usually inanimate:
  e.g. a quantity of coins (countable) / a quantity of money (uncountable).
  ‘Quantity’ is more formal than ‘amount’ or ‘number’.
  ‘Quantity’ is often used with an adjective such as big, large, huge, small, tiny, considerable, significant...
  • The police discovered a considerable quantity of weapons (countable).
  • We checked that there was a sufficient quantity of water (uncountable).
  • The volunteers prepared large quantities of food (uncountable).
  • A huge quantity of potatoes (countable) will be delivered.
  • The restaurant ordered an enormous quantity of strawberries (countable).
  • A small quantity of wine (uncountable) is produced in the area.
  • We deliver large quantities of wood (uncountable) during the winter.
  • Vast quantities of oil (uncountable) covered the water around the ship.