A mortgage in principle, sometimes referred to as an Agreement in Principle (AIP) or Decision in Principle (DIP), is a document provided by a mortgage lender that indicates how much they may be willing to lend you. While it is not a formal mortgage offer, it is often required by estate agents and sellers when you’re house hunting in the UK. Understanding how long a mortgage in principle lasts is important to ensure it remains valid during your property search and offers a clearer picture of your borrowing potential.

We’ll explore the typical duration of a mortgage in principle, what factors affect its validity, how to renew it if necessary, and how it fits into the overall mortgage process.

What Is a Mortgage in Principle?

A mortgage in principle is a preliminary indication from a lender suggesting how much they might lend you, based on a basic assessment of your income, outgoings, and credit history. It is not a binding commitment but serves as an initial check to help assess your borrowing capability. Many homebuyers obtain one before they start viewing properties as it demonstrates to sellers and estate agents that they are serious and financially prepared.

It’s worth noting that a mortgage in principle does not guarantee that a full mortgage application will be successful. A more detailed assessment will be conducted when you apply for a full mortgage, including a valuation of the property and comprehensive checks on your financial situation.

How Long Does a Mortgage in Principle Last?

The duration of a mortgage in principle typically lasts between 60 and 90 days, depending on the lender. However, some lenders may offer AIPs that are valid for as little as 30 days or extend up to 120 days. It varies significantly between providers, as each lender has its own policies and criteria.

While an AIP can provide reassurance when beginning your property search, it is important to be aware of the expiry date and whether you may need to request a renewal if your property search extends beyond that timeframe.

Common AIP Validity Periods by Lender

Although these are illustrative figures, here are some general examples of how long AIPs may last with major UK lenders (please check directly with each lender for current validity):

Nationwide: Valid for 90 days
Barclays: Valid for 90 days
Halifax: Valid for 30 to 90 days
NatWest: Valid for around 60 days
HSBC: Valid for 60 to 90 days

These durations are not guaranteed and should be checked directly with the relevant lender or mortgage adviser when obtaining an AIP.

What Happens When a Mortgage in Principle Expires?

If your mortgage in principle expires before you find a property or before your mortgage application is submitted, you will need to obtain a new one. In most cases, renewing an AIP is straightforward, especially if your financial circumstances have remained the same. However, changes in your credit profile, employment, or income could impact the lender’s willingness to provide the same amount or any loan at all.

Lenders may carry out a fresh credit check when you apply for a new AIP, which is something to consider if you are applying for multiple agreements in a short space of time. Each credit check could potentially affect your credit score, depending on whether the lender carries out a soft or hard credit search.

Soft vs. Hard Credit Searches

When applying for a mortgage in principle, lenders will carry out either a soft or hard credit check:

Soft Credit Search: This type of search doesn’t affect your credit score and isn’t visible to other lenders. It gives the lender a brief overview of your financial history to assess risk.
Hard Credit Search: This appears on your credit report and may affect your credit score, especially if several hard checks are made in a short period.

If you’re unsure which type of check a lender uses, it’s worth confirming in advance, particularly if you’re planning to renew your AIP multiple times or apply with different lenders.

Can a Mortgage in Principle Be Renewed?

Yes, most lenders allow you to renew your mortgage in principle if it expires and you’re still searching for a property. The renewal process is often quicker than the initial application, especially if your financial situation hasn’t changed. However, the lender will reassess your circumstances and may need to run another credit check.

You may also need to re-submit recent documents, such as payslips, bank statements, or proof of ID if your original submission is no longer valid due to age. Lenders typically require the most up-to-date documentation, especially if your AIP is being renewed after a few months.

What Can Affect the Validity of a Mortgage in Principle?

Even if your AIP is still within its stated validity period, certain changes in your personal circumstances could mean it no longer reflects your true borrowing potential. These include:

Changes in employment or income
Taking on new debt or financial commitments
Missed payments or adverse credit entries
Changes in living arrangements or dependants
Significant outgoings that weren’t declared previously

If any of these apply after receiving your AIP, it’s sensible to update your information with the lender or speak to a mortgage adviser who can help you understand how these factors may influence your borrowing options.

Does a Mortgage in Principle Guarantee You a Mortgage?

One of the most important things to remember is that a mortgage in principle does not guarantee that you’ll be approved for a full mortgage. It’s based on a preliminary assessment and subject to change once the lender carries out a full underwrite. During the full application process, the lender will check your documents in detail, carry out a property valuation, and review your finances in more depth.

Therefore, while an AIP is a useful tool in giving you an idea of what you may be able to borrow, it’s not legally binding and does not form an offer of finance. Once you have had an offer accepted on a property, you’ll need to submit a formal mortgage application for a definitive decision.

How Important Is Having a Mortgage in Principle?

Having a valid mortgage in principle can be an essential step in today’s competitive property market. Here’s why many homebuyers seek one early in the process:

It helps you understand how much you might be able to borrow
It shows sellers and estate agents that you’re a serious buyer
It can speed up the process once you find a property you want to buy

Some estate agents may even ask to see an AIP before allowing you to view properties or submit offers. Keeping it up to date throughout your house-hunting journey can offer reassurance and practical benefits.

What Documents Are Needed for a Mortgage in Principle?

While the specific requirements vary by lender, you will usually need to provide basic information to receive a mortgage in principle. This typically includes:

Full name and address
Employment details and income
Outgoings and debts
Credit commitments
Address history
Details of the deposit amount

Some lenders may ask for supporting documentation even at the AIP stage, although it’s more common that this is required during a full mortgage application. When working with a mortgage adviser, they will help gather and assess these documents to ensure accuracy.

How Many Times Can You Renew a Mortgage in Principle?

There is no strict limit on the number of times you can renew a mortgage in principle. However, it’s important to consider how frequent applications may impact your credit file, particularly if the lender conducts hard credit searches each time. If you find yourself needing repeated renewals, it may be worth reviewing your property criteria or speaking with a mortgage adviser who can help you reassess your affordability and strategy.

Does a Mortgage in Principle Affect Your Credit Score?

If the lender performs a soft credit search, there will be no impact on your credit score. However, if a hard credit search is undertaken, it may leave a mark on your file that other lenders can see. Too many hard searches in a short space of time could raise questions from future lenders. This means it’s important to be strategic about how often and with whom you apply for an AIP.

Working with a mortgage adviser can help reduce unnecessary applications and ensure you only request an AIP when appropriate.

Mortgage in Principle vs. Mortgage Offer

It’s easy to confuse a mortgage in principle with a mortgage offer, but they are quite different:

Mortgage in Principle: An informal estimate of how much a lender might be willing to lend you, based on basic financial information.
Mortgage Offer: A binding offer of finance issued after a full application, credit check, and property valuation have been completed.

The mortgage offer is the document lenders issue when they have completed full underwriting and are satisfied with all the information and the property itself.

Key Takeaways

Mortgage in principles usually last between 30 and 90 days, depending on the lender.
You can renew your AIP, but your financial circumstances may be reassessed each time.
Changes in your situation can affect borrowing potential even within the AIP validity period.
Repeated applications may impact your credit score if hard credit checks are performed.
An AIP is not legally binding and does not guarantee a full mortgage offer.

Final Thoughts

Understanding how long a mortgage in principle lasts and how it fits into the wider mortgage application journey can help you stay well prepared throughout the homebuying process. While it’s a useful tool for planning and negotiating, it’s not a guarantee of funding. Keeping your AIP up to date and working with a mortgage adviser can help you stay informed and confident as you work towards your home purchase.