A surcharge is an extra charge added to the cost of a good or service. It is added to an existing tax but not included in the stated price of the good or service. In the context of Income-tax, it may be called a tax on tax because it is levied on tax payable and not the income generated. It is an additional charge payable on income tax, added tax for the taxpayers who have a higher income in a financial year. There is also a facility of marginal relief for individuals, firms, and companies to save them from the surcharge.
In terms of payment systems, a surcharge is also known as a checkout fee. It is an extra fee charged by a merchant when receiving payment by cheque, credit card, charge card, or debit card. The amount is such that it covers the cost to the merchant of accepting that means of payment, such as the merchant service fee imposed by a credit card company or bank.