Understanding Mortgage Agreement In Principle: A Guide for Home Buyers
Updated: 12 hours ago
Buying a home can feel a little overwhelming, especially if you're a first-time buyer. One of the first steps is understanding your Mortgage Agreement in Principle (AIP) and how it can help you prepare for your property search.
Also known as a mortgage in principle or Decision in Principle (DIP), an AIP gives you an indication of how much a lender might be willing to lend you. It can help you set a realistic budget, approach estate agents with confidence and prepare for the next stage of buying a home.
In this guide, we'll explain how to get a mortgage agreement in principle, how long it lasts, whether it affects your credit score and what happens next.
What is a Mortgage Agreement in Principle?
A Mortgage Agreement in Principle is a written estimate from a bank or building society that provides you with an indication of how much you can borrow. You can obtain this either from your mortgage adviser or from your bank / building society if that is your preferred route.
You may also hear an Agreement in Principle referred to as a Mortgage in Principle (MIP) or Decision in Principle (DIP). Although lenders use different terminology, these generally refer to the same initial indication of how much you may be able to borrow.
Your lender will consider the information you provide about your income, outgoings and financial circumstances to assess your potential borrowing. This can help you understand your mortgage affordability before you start viewing properties.
What are the Benefits of an AIP?
An AIP is a great first step for buyers looking to purchase a property. Having one can bring peace of mind not only when you begin your search, but also when you are ready to make an offer. Estate Agents and sellers alike will appreciate that you have this agreement in principle since it demonstrates financial stability and that you are serious about purchasing a property.
Getting a mortgage agreement in principle before buying a house can help you establish a realistic property budget and narrow down your search. It can also reassure estate agents and sellers that you've taken steps to understand your mortgage options.
If you're a first-time buyer, having an AIP in place can be particularly helpful when you're ready to make an offer. Just remember that it isn't a guaranteed mortgage offer, and the lender will still need to assess your full application.
Will I Receive Anything in Writing?
After receiving the green light with your mortgage AIP, you can expect to receive a certificate from the lender that provides evidence of your readiness to move forward. This document, often referred to as a Mortgage AIP Certificate, is helpful evidence when meeting with an estate agent or seller.
How do I Obtain an AIP?
To get a mortgage agreement in principle, you'll usually need to provide details about your income, regular outgoings, existing credit commitments, deposit and address history. Your lender or mortgage adviser can explain exactly what's required for your circumstances.
It's worth getting your information and supporting documents ready early. Reviewing your finances in advance can help identify any potential issues with mortgage affordability or your credit history before you move on to a full mortgage application.
At Beechwood Mortgages, we can help you understand your options and identify a suitable route forward based on your individual circumstances.
You will need to share your details with your mortgage adviser (or your bank / building society if this is your preferred route), which should include providing all your documents beforehand too. By providing your documents early into the process will ensure that you are in the best position possible for approval and that nothing has been overlooked. (we’ve often seen mortgage decisions change / retracted when documents have been provided further down the line, so avoid falling foul of this by supplying everything upfront).
How Long Does an AIP Last?
Most lenders offer their AIP’s for between 30 and 90 days. However, all is not lost if yours runs out, providing there have been no changes to your income or expenditure your AIP can generally be updated with relative ease.
Can an AIP be Withdrawn?
When applying for a loan, an AIP can give you an indication of the amount that might be available to borrow. However, it’s important to remember that changes in circumstances could affect your application – such as having fewer funds saved up or switching jobs. Make sure all your information is current and accurate if you want the best chance of success.
What Happens if My AIP is Declined?
If your mortgage agreement in principle is declined, don't automatically assume you won't be able to get a mortgage. Different lenders have different lending criteria, and a decision can depend on your income, credit history, existing commitments and overall financial circumstances.
Before making another application, it's worth understanding why the AIP was declined. Reviewing your credit report and speaking to a mortgage adviser can help you identify potential issues and explore whether another lender may be more suitable.
A declined AIP isn't the same as having a full mortgage application declined, but it's important to understand the reason before taking the next step.
Do not worry if you are rejected by a lender. They all vary and operate their own individual credit score process, so where one lender may not support you it is likely that another will. It’s always best practice to keep an eye on your credit file and there are several agencies that the lenders use when reviewing your past history, most notably Equifax, Experian, CheckMyFile and ClearScore being the most used.
Does a Mortgage Agreement in Principle Affect Your Credit Score?
It’s important to be aware that if you decide to get an AIP, it could affect your credit score. This is because a form of check – either ‘hard’ or ‘soft’- usually has to take place in order for the application process to be complete. Whilst lenders and mortgage advisers may use soft checks so as not leave any visible trace on your records, applying several times within a short space of time can still have an adverse effect on your credit rating.
When applying for a mortgage agreement in principle, it's worth checking whether the lender will carry out a soft or hard credit search. A soft search generally doesn't affect your credit score, whereas a hard search leaves a record on your credit file and can be visible to other lenders.
The type of credit check used depends on the lender, so don't assume every AIP works in the same way. If you're unsure, a mortgage adviser can help you understand the process before you apply.
Understanding the difference between soft and hard credit searches can be an important part of managing your finances. Soft checks are done by lenders to assess eligibility for specific products, which you will be able to see on your own report but have no effect on your score. On the other hand, a hard search occurs when submitting an application for a loan or credit – it is visible to everyone and may temporarily reduce your rating (depending how often you borrow). So think carefully before taking out any loans!
How Does My Credit Score Affect My AIP?
Your credit score is more than just a number – it’s an indicator of your financial reliability. It can be the difference between getting accepted on favourable rates on loans and being turned away, so taking steps to keep yours high pays off in the long run.
How Can I Improve My Credit Score?
Your credit score is strongly impacted by how you manage your money and debts – for better or worse. Positive actions such as paying bills on time, establishing a good relationship with lenders, and being registered to vote can all play an important role in ensuring that your financial profile reflects healthy borrowing behaviour. On the flip side; missing payments, defaults or other delinquent activities could have significant implications when it comes to obtaining new lines of credit further down the road. For more tips visit How To Improve Your Credit Score.
If you are concerned about your credit score you may also find 5 Tips for Securing a Mortgage with Less than Perfect Credit helpful too.
In conclusion, a mortgage agreement in principle (AIP) is an essential step in the home buying process for anyone looking to secure a mortgage. By understanding what an AIP is and how to obtain one, you are setting yourself up for success when it comes time to make an offer on your dream home. Working with a mortgage adviser can greatly simplify the AIP process, as they have the expertise and resources to guide you through it smoothly. You can speak to a mortgage adviser at Beechwood today to get your AIP underway and take the first step towards your new home.
Remember, an AIP is not a guaranteed offer of a mortgage, but it does provide valuable insight into your borrowing potential and can give you an advantage in a competitive housing market. Keep in mind that improving your credit score before applying for an AIP can also increase your chances of approval and potentially lower your interest rates. So why wait?
To discuss how we can help secure your mortgage AIP and put you one step closer to owning your own home. Your dream of homeownership is within reach, and we are here to help make it a reality.
What Happens After You Get a Mortgage Agreement in Principle?
Once you have your mortgage agreement in principle, you can start looking at properties within your estimated budget. You may also be in a better position to discuss making an offer with an estate agent.
When you've found a property and had an offer accepted, the next step is usually to progress to a full mortgage application. Your lender will ask for further information, check your supporting documents and assess the property before deciding whether to issue a formal mortgage offer.
Remember, an AIP is an initial indication rather than a guarantee. Your final mortgage approval will depend on the lender's full assessment of your circumstances and the property you're buying.
Just about to make an offer on a property? Check out How to Make an Offer on a Property and My Offer Has Been Accepted, What Happens Next? for some top tips.
Your property may be repossessed if you do not keep up repayments on your mortgage
Written and Published: 2 June 2023 | Last updated: 29 October 2026 by Adrian Collins, Founder of Beechwood Mortgages (FCA Ref: 219335). Reviewed and Approved by Stonebridge Mortgage Solutions Limited, which is authorised and regulated by the Financial Conduct Authority (FCA Ref: 454811).
