Mortgage Agreement in Principle: What Is It?

An agreement in principle gives you an indication of how much a lender is willing to let you borrow, based on a preliminary assessment of your finances. It's a useful step before making a full mortgage application.

What an Agreement in Principle Means

An agreement in principle (AIP), also called a decision in principle (DIP) or mortgage promise, is a statement from a lender confirming they would, in principle, be willing to lend you a certain amount. It's based on a basic assessment of your income, outgoings, and credit history, but it's not a guarantee of a mortgage offer.

The AIP tells you roughly how much you could borrow, which helps you understand your budget when looking at properties or comparing remortgage deals. However, the lender will carry out more detailed checks — including a full credit search and property valuation — before making a formal offer.

How to Get an Agreement in Principle

You can apply for an AIP online with most UK lenders, through a mortgage broker, or in branch. The process typically takes minutes and requires basic information about your income, employment, existing debts, and the property you're looking to mortgage or remortgage.

Most lenders now use a soft credit check for the AIP, meaning it won't affect your credit score. However, some still perform a hard check, so it's worth confirming beforehand. If you're shopping around, stick to lenders that use soft searches so you can compare options without leaving multiple footprints on your file.

How Long Does an AIP Last?

Most agreements in principle are valid for 60 to 90 days, depending on the lender. After this period, the AIP expires and you'd need to apply for a new one. Your circumstances or the lender's criteria may have changed in the interim, so a renewed AIP isn't guaranteed to match the original.

For remortgaging, the AIP is most useful once you've decided to switch and want to confirm your eligibility before proceeding with a full application. Since many lenders let you apply for a remortgage up to six months before your current deal ends, you can get your AIP early and move forward with confidence.

AIP vs Full Mortgage Offer

It's important to understand that an AIP is not the same as a mortgage offer. The AIP is a preliminary indication based on limited information. A full mortgage offer comes after the lender has:

The lender may offer a different amount from the AIP, or they may decline to lend altogether if the full assessment reveals issues not apparent from the initial check. For this reason, don't treat an AIP as a guaranteed commitment from the lender.

Important: Your home may be repossessed if you do not keep up repayments on your mortgage. There will be a fee for mortgage advice. The actual rate available will depend on your circumstances. Think carefully before securing other debts against your home.

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Frequently Asked Questions

It depends on the lender. Most now use a soft credit check for AIPs, which doesn't affect your score. A few still use a hard check, which can cause a small temporary dip. Always ask the lender or broker whether the AIP involves a soft or hard search before proceeding, especially if you're applying to multiple lenders.

An AIP isn't strictly required to remortgage, but it's a useful step. It confirms that a lender is likely to approve your application before you commit to the full process. It also helps you compare what different lenders might offer, allowing you to make a more informed decision about which deal to pursue.

Yes. An AIP is not a guarantee. You can still be declined at the full application stage if the detailed credit check, income verification, or property valuation raises issues. Common reasons include undisclosed debts, changes in employment, or the property not meeting the lender's criteria. Getting an AIP and then being declined is frustrating, but it's relatively common.

Yes, and it can be a sensible approach — provided you use lenders that perform soft credit checks. This lets you compare how much different lenders are willing to offer without affecting your credit score. A mortgage broker can also provide this comparison without needing multiple individual AIPs.