A mortgage in principle (MIP) is a certificate issued by a lender before you make a full mortgage application.
It is sometimes called an Agreement in Principle or Decision in Principle.
The document means that a lender would 'in principle' lend you a certain amount of money to buy a property.
It can also be called a Decision in Principal or Agreement in Principle.
A Mortgage in Principal shows estate agents that you will be able to get a mortgage and shows sellers that you are a serious buyer and puts you in a good position against other potential buyers that don’t have one.