A Decision in Principle (DIP) is a preliminary indication from a mortgage lender of how much they would be willing to lend you. It is based on the financial information you provide — your income, deposit, and outgoings — along with a basic credit check. Some lenders call this an Agreement in Principle (AIP), but they mean the same thing.
How it differs from a full application
A DIP is not a mortgage offer. It is a statement that, based on the information provided, the lender would in principle be prepared to lend you a certain amount. A full mortgage application comes later, once you have found a property. At that stage, the lender will verify your income, carry out a full credit check, and arrange a valuation of the property. It is possible to be approved at DIP stage but declined at full application if the detailed checks reveal something different from what was initially declared.
Soft vs hard credit search
This is an important distinction. A soft credit search is only visible to you and does not affect your credit score. A hard search is visible to other lenders and can temporarily lower your score. Most lenders now use a soft search for DIPs, but some still use a hard search. If you are shopping around, it is worth checking which type each lender uses before applying, especially if you plan to approach several lenders.
How long does a DIP last?
Most DIPs are valid for around 90 days, though this varies by lender — some last 60 days, others up to 6 months. After it expires, you would need to apply again. A DIP can be useful when making an offer on a property, as it shows estate agents and sellers that you are a serious buyer who has already been assessed by a lender. It is not a guarantee of a mortgage, but it does carry weight in a competitive market.
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Check Your AffordabilityLast updated: April 2026
