Agreement in principle (AIP / DIP) explained
An agreement in principle (AIP), also called a decision in principle (DIP), is an early indication from a lender of roughly how much it might lend, based on a quick check of your income and credit. It is not a full mortgage offer, but it shows sellers you are a serious buyer. Some lenders use a soft credit check (no footprint), others a hard one. It usually lasts around 30 to 90 days.
What it is for
An AIP does two useful things. It gives you a realistic borrowing figure before you start viewing, so you shop in the right price range. And it reassures estate agents and sellers that an offer from you is credible, which can matter in a competitive market. It is a quick, early step, not the full underwrite.
Soft check or hard check
Lenders differ on the credit search used for an AIP. A soft check is visible only to you and leaves no footprint; a hard check is recorded and, if repeated several times in a short period, can make lenders more cautious. Before you request an AIP, it is worth knowing which the lender uses. A broker can run agreements in a way that protects your credit file.
What it does not do
- It is not a mortgage offer: the full application can still change the outcome.
- It does not value the property: that happens at full application.
- It is a snapshot: a change in your circumstances can change the result.
- It usually expires after around 30 to 90 days, though it can be renewed.
Common questions
What is an agreement in principle?
An agreement in principle (AIP), also called a decision in principle (DIP) or mortgage in principle, is an early indication from a lender of roughly how much it might lend you, based on a quick check of your income and credit. It is not a full mortgage offer, but it shows estate agents and sellers you are a serious buyer.
Does an AIP affect my credit score?
It can. Some lenders use a soft credit check for an AIP, which does not affect your file, while others use a hard check, which leaves a footprint. It is worth asking which a lender uses, and avoiding lots of hard-check AIPs in a short space of time.
How long does an AIP last?
Typically around 30 to 90 days, depending on the lender. If it expires before you find a property, it can usually be renewed. It is a snapshot, so a material change in your circumstances can change the outcome at full application.
Is an AIP a guarantee of a mortgage?
No. It is an indication, not an offer. The full application involves a deeper assessment, a property valuation and document checks, and the lender can still decline or lend less. Treat the AIP as a strong signal, not a certainty.
Next, see how much can I borrow and the documents you need.
Founder, MortgageExplained, MortgageExplained
Adam spent nearly a decade as a mortgage adviser at Just Mortgages, with further experience in commercial finance. He is CeMAP and CF qualified. He built MortgageExplained to do one thing well: explain mortgages in plain English, then introduce you to a regulated broker when you are ready. Every page is written and reviewed by Adam.
Last reviewed: 21 July 2026