Fixed costs are those that are independent of output. They should be paid even if firm produces no output. They wouldn't change even if output changes. They remain fixed whether output is small orlarge. Fixed costs are also known as 'overhead costs', 'sunk costs' or 'supplementary costs'. They include payments likeinterest, rent, depreciation charges, insurance, maintenance costs, administrative expenselike manager's salary, property taxes and so on. In the short period, total amount of these fixed costs won't decrease or increase when the volume of firms output falls orrises.