Mortgage in principle UK: what it is and how to get one

A mortgage in principle UK lenders issue is a conditional indication of how much they might lend you, based on a quick check of your income, outgoings, and credit history. You'll also hear it called an agreement in principle (AIP), a decision in principle (DIP), or a "mortgage promise" - different lenders use different names, but they all mean the same thing.

It's important to understand what a mortgage in principle is not. It is not a formal mortgage offer, it carries no legal obligation on you or the lender, and it doesn't involve a property valuation. If you go on to buy a home and take out a full mortgage, remember that your home may be repossessed if you do not keep up repayments on your mortgage or any other debt secured on it.

If you're moving home rather than buying for the first time, read our moving home mortgage guide for the wider process, including how a mortgage in principle fits alongside selling your current property.

Whichever term a lender uses, the underlying process is the same: they'll ask for some basic financial information, run a quick credit check, and give you an indication of how much you could borrow. None of these terms represent a guarantee that your full mortgage application will be approved.

Most estate agents in England and Wales now expect to see a mortgage in principle before they'll book you in for a viewing, let alone accept an offer. Having one ready puts you in a stronger position from the start.

• Budget clarity - you'll know roughly what you can borrow before you fall in love with a property that's out of reach.
• Credibility with estate agents - sellers and agents take your offer more seriously when it's backed by evidence you can borrow the money.
• Faster offer acceptance - in a competitive market, a mortgage in principle can be the difference between your offer being accepted or overlooked.
• An early flag of credit issues - if something in your credit history is going to cause a problem, it's far better to find out now than after you've made an offer.

If you're an existing homeowner selling and buying at the same time, a mortgage in principle also reassures the seller of your onward purchase that your side of the chain is financially credible. It's worth running your numbers through a mortgage affordability calculator before you apply, so the amount you ask for is realistic for your income and outgoings.

Keep in mind a mortgage in principle is based on the information you provide and a quick credit check - it isn't a guarantee you'll be approved once a lender examines your finances in full at the full application stage.

Getting a mortgage in principle UK-wide is usually quick, whether you apply directly with a lender or speak to a broker first. Before you start comparing products, including fixed rate mortgage options, it helps to know what the process actually involves.

Every lender asks for broadly the same details, whether you're applying directly or through a broker.

If you're self-employed or work as a contractor or freelancer, lenders will usually ask for SA302 tax calculations or two to three years of accounts instead of payslips. Read our guide on self-employed mortgage in principle applications for more detail on what different lenders accept.

Applying directly with a lender limits you to that one lender's criteria. If your profile doesn't fit - because of self-employed income, a small deposit, or a less-than-perfect credit history - you may be declined even though another lender would have said yes.

A broker who compares a wide range of lenders can match your circumstances against multiple lenders' criteria before you apply, reducing the risk of unnecessary hard credit searches from repeated rejections. For home movers with a more complex profile, such as an existing mortgage to sell alongside variable income, this route often makes the process smoother. Keep in mind that no broker, however wide their panel, can access every lender in the market.

Whichever route you choose, you can check a firm's authorisation on the Financial Conduct Authority register before you share any financial information.

Most mortgage in principle credit score checks use a soft search, which means the check is visible to you but not to other lenders, and it has no impact on your credit score. A smaller number of lenders use a hard search for a mortgage in principle, which does leave a visible mark on your credit file.

Before you apply, ask the lender or your advisor whether they use a soft or hard search for a mortgage in principle. Whatever type is used at this stage, your full mortgage application will always involve a hard credit search once you've had an offer accepted on a property.

A mortgage in principle typically lasts between 60 and 90 days, though some lenders set the validity period at 30 days. If it expires before you've found a property or had an offer accepted, you can usually renew it, which normally involves another soft search rather than a full new application.

Lending criteria and product ranges can shift over time, so it's worth checking with your lender or advisor that your mortgage in principle is still valid and reflects your current circumstances before you use it to make an offer, particularly if some time has passed since you first applied.

Once you have your agreement in principle in hand, there are a few more steps between finding a property and moving in.

The full process from application to mortgage offer typically takes two to six weeks, depending on the lender and how complex your circumstances are. If you're part of a property chain, factor in extra time, since delays anywhere in the chain can affect your own timeline. Once you accept a formal mortgage offer, remember that your home may be repossessed if you do not keep up repayments on your mortgage or any other debt secured on it.

A mortgage in principle declined outcome isn't the end of the road, but how you respond matters.

• Don't immediately apply elsewhere. Applying to several lenders in quick succession can mean multiple hard searches, which may lower your credit score further.
• Check your credit report. Get copies from Experian, Equifax, and TransUnion, and look for errors or accounts you don't recognise.
• Review your debt-to-income ratio. Outstanding credit cards, loans, or overdrafts all reduce how much a lender will consider offering you.
• Reconsider the amount you're asking for. A smaller mortgage in principle with more deposit or a lower purchase price may be realistic where a larger one wasn't.
• Speak to a broker. An advisor can point you toward lenders with more flexible criteria, including specialist options for adverse credit. If you're concerned about your credit history more broadly, read our guide on mortgage in principle with bad credit.

If money worries or debt are affecting your ability to move forward, impartial, government-backed guidance is available from MoneyHelper on 0800 138 7777.