Mortgage in principle UK

Getting a mortgage in principle is one of the most important steps to take before seriously searching for a home in the UK.

It gives you an indication of how much a lender may be prepared to lend based on information about your income, spending and financial circumstances. More importantly, it helps turn an uncertain property search into a realistic buying budget.

For a first-time buyer, this matters even more. You don’t want to spend weeks viewing properties in London only to discover that the mortgage you expected to get is unavailable or insufficient for the property you want.

A mortgage in principle can also demonstrate to sellers and estate agents that you have started arranging your finance. However, it is important to understand what it does — and does not — guarantee. A mortgage in principle is not a formal mortgage offer, and your final application will still be subject to detailed affordability checks, documentation and an assessment of the property.

This guide explains exactly how to get a mortgage in principle in the UK, what information you need, how long it takes, whether it affects your credit score, what happens after you receive one and how a mortgage broker can help you choose the right route.

Key Takeaways

  • A mortgage in principle (MIP), Agreement in Principle (AIP) and Decision in Principle (DIP) generally describe the same type of preliminary borrowing assessment.
  • An MIP gives you an indication of how much a lender may be willing to lend; it is not a guarantee of mortgage approval.
  • You will typically need information about your income, expenditure, deposit and address history.
  • Some lenders use a soft credit search while others use a hard search, so check how the lender will assess your credit before applying.
  • An MIP is commonly valid for around 30 to 90 days, although this varies between lenders.
  • Getting your MIP before making serious property offers can help you establish a realistic budget and demonstrate that you are financially prepared.
  • Your final mortgage approval can still be declined even if you have an MIP because the lender must assess both you and the property.
  • A mortgage broker can help you identify lenders whose criteria fit your circumstances before you make a full application.

Table of Contents

What Is a Mortgage in Principle?

A mortgage in principle is an indication from a mortgage lender of how much it might be prepared to lend you based on information you provide.

It is sometimes called:

  • Mortgage in Principle (MIP)
  • Agreement in Principle (AIP)
  • Decision in Principle (DIP)

The terminology varies between lenders, but the underlying purpose is similar.

MoneyHelper describes an MIP as an estimate of how much a lender may offer and notes that it can help you establish your potential property budget before you apply for a mortgage.

For example, suppose you have:

  • Deposit: £50,000
  • MIP: £400,000
  • Potential property budget: approximately £450,000

This doesn’t mean you should spend £450,000.

It means the lender has indicated that, based on the information available at that stage, it may be prepared to lend around £400,000.

Your actual comfortable budget may be lower once you account for Stamp Duty, legal fees, service charges, insurance, moving costs and your normal household expenditure.

An MIP Is Not a Mortgage Offer

This distinction is critical.

An MIP does not mean:

“The bank has approved my mortgage.”

It means:

“Based on the information assessed so far, the lender may be willing to lend this amount.”

Your final mortgage application will involve more detailed checks.

The lender will assess your documentation, financial circumstances and the property you want to purchase before issuing a formal mortgage offer.

Mortgage in Principle vs Agreement in Principle vs Decision in Principle

You may see all three terms when researching mortgages.

TermWhat it means
Mortgage in PrinciplePreliminary indication of potential borrowing
Agreement in PrincipleGenerally the same concept
Decision in PrincipleGenerally the same concept

Don’t become distracted by the terminology.

The more important questions are:

Who is providing it?

How much are they indicating you may be able to borrow?

What information and checks were used?

How long is it valid?

Was a soft or hard credit search carried out?

These details can matter considerably more than whether the document says MIP, AIP or DIP.

Why Should You Get a Mortgage in Principle?

You don’t legally have to obtain a mortgage in principle before buying a property.

However, there are several reasons why it can be useful.

1. It Helps Establish Your Property Budget

Without an MIP, you may be estimating your budget based on online mortgage calculators or assumptions about your income.

An MIP provides a more lender-specific indication.

MoneyHelper explains that an MIP can help you understand your homebuying budget, particularly when combined with your deposit.

2. It Can Strengthen Your Position With Sellers

If you’re competing against other buyers, being able to demonstrate that you have finance in principle can show that you are serious about purchasing.

GOV.UK recommends getting a decision in principle before viewing properties because it provides an indication of your borrowing capacity and signals to sellers that you are serious.

This doesn’t guarantee that your offer will be accepted.

But it can make you appear more prepared.

3. It Helps Prevent Unrealistic Property Searches

Imagine you earn £60,000 and assume you can comfortably buy a £500,000 property.

After speaking to a lender, you discover that your existing debts and monthly expenditure reduce your potential borrowing.

Finding this out before you start making offers is far better than discovering it after you’ve found your dream property.

4. It Can Help You Move Faster

Once you’ve found a property and your offer has been accepted, having already gathered much of your financial information can make the transition into the full mortgage application more straightforward.

It doesn’t eliminate underwriting.

But it means you aren’t starting from zero.

When Should You Get a Mortgage in Principle?

The ideal time is generally before you begin seriously viewing and making offers on properties.

You don’t necessarily need one months before you intend to buy.

Because MIPs have limited validity, timing matters.

MoneyHelper says they commonly remain valid for around 30 to 90 days, depending on the provider.

A practical sequence is:

Prepare finances → Get MIP → Search for property → Make offer → Full mortgage application

For example, if you’re planning to start viewing properties in October, you might arrange your MIP shortly before your search begins rather than obtaining one many months earlier and allowing it to expire.

What If Your MIP Expires?

Don’t panic.

An expired MIP doesn’t mean you can no longer obtain a mortgage.

You may simply need to obtain a new one.

However, your circumstances or the lender’s available products may have changed since the original assessment.

MoneyHelper confirms that an MIP can generally be reapplied for when it expires.

What Information Do You Need for a Mortgage in Principle?

Getting an MIP is usually much simpler when you have your financial information ready.

You may need:

  • Full name
  • Date of birth
  • Address history
  • Employment details
  • Annual income
  • Additional income
  • Monthly expenditure
  • Existing debts
  • Credit commitments
  • Deposit amount
  • Information about the property you intend to buy, where applicable

MoneyHelper states that applicants may need to provide income, spending, address history and deposit information when obtaining an MIP.

Employed Applicants

You may need details such as:

  • Basic salary
  • Bonuses
  • Commission
  • Overtime
  • Second-job income
  • Other regular income

Whether additional income is accepted — and how much of it is counted — varies between lenders.

Self-Employed Applicants

Self-employed applicants may need more extensive evidence of income.

This can include:

  • Business accounts
  • Tax calculations
  • Tax year overviews
  • Bank statements
  • Details of business income

MoneyHelper notes that self-employed applicants may typically be asked for two or three years of tax returns and business accounts, although lender requirements vary.

If you’re self-employed and buying in London, see our dedicated guide to self-employed mortgages in London.

How to Get a Mortgage in Principle: Step-by-Step

The process is relatively straightforward, but preparation can make a significant difference.

Step 1: Calculate Your Available Deposit

Before approaching a lender, establish exactly how much you have available.

Include legitimate sources such as:

  • Personal savings
  • Lifetime ISA funds where eligible
  • Gifted deposit
  • Other acceptable sources of funds

Don’t assume every pound in your bank account can automatically be treated as your deposit.

You should also keep money aside for buying costs.

Step 2: Work Out Your Income

Calculate your reliable annual income.

If you’re employed, this may start with your basic salary.

If you receive bonuses, commission, overtime or income from other sources, establish what documentation you have available and whether it is consistent.

Step 3: Review Your Monthly Spending

Lenders don’t simply look at how much you earn.

They consider your outgoings as part of affordability.

This can include:

  • Loans
  • Credit cards
  • Car finance
  • Childcare
  • Council tax
  • Utilities
  • Insurance
  • Travel
  • Other regular household spending

MoneyHelper confirms that lenders assess income alongside household spending and existing financial commitments.

Step 4: Check Your Credit Report

Before applying, review your credit reports.

Check for:

  • Incorrect information
  • Missed payments
  • Defaults
  • Financial associations
  • Incorrect addresses
  • Other potential issues

GOV.UK recommends understanding which type of credit search will be used because some MIP applications involve hard searches.

Step 5: Choose How You Want to Apply

You can approach:

A lender directly

or

a mortgage broker/adviser.

A direct lender can generally discuss its own mortgage products.

A broker may be able to compare products from multiple lenders, depending on the scope of their service.

MoneyHelper distinguishes between advisers tied to a particular lender and independent brokers who can access products from multiple providers.

Step 6: Complete the MIP Application

You’ll provide the required information about your:

  • Income
  • Spending
  • Deposit
  • Employment
  • Address history
  • Financial circumstances

The lender then assesses the information and determines whether it is prepared to provide an indication of borrowing.

Step 7: Check the Credit Search Type

Before submitting an application, find out whether the lender will perform a:

Soft search

or

Hard search.

This matters if you’re comparing different mortgage options.

Some lenders use soft searches for an MIP, while others use hard searches.

Step 8: Receive Your Mortgage in Principle

Depending on the lender and your circumstances, you may receive your MIP very quickly.

Some online systems can provide an initial decision within minutes or hours when the required information is available.

You’ll then have an indication of the amount you may be able to borrow.

Step 9: Start Your Property Search

Now you have a much clearer starting point.

Your property budget should be based on:

MIP + deposit − purchase costs − appropriate financial buffer

Don’t automatically spend every penny of the MIP.

How Much Can You Borrow With a Mortgage in Principle?

Your MIP borrowing amount depends on your financial circumstances and the lender’s affordability criteria.

MoneyHelper says lenders consider income, outgoings and employment security, with many lenders historically using a loan-to-income limit around 4.5 times annual income, although most people are offered less and individual lending criteria vary.

For illustration:

If your household income is £80,000, a simple 4.5-times calculation would produce:

£80,000 × 4.5 = £360,000

But that does not mean you are automatically entitled to borrow £360,000.

Your existing debts, spending, deposit, credit profile and other circumstances can affect the result.

Some lenders may also have different approaches to affordability.

Your Deposit Still Matters

Suppose your MIP indicates potential borrowing of £360,000.

With a £40,000 deposit, your theoretical property budget could be around:

£360,000 + £40,000 = £400,000

But you still need to account for purchase costs.

This is why an MIP should be treated as a borrowing indicator, not a shopping voucher.

Does a Mortgage in Principle Affect Your Credit Score?

It can.

The impact depends on the type of credit search performed by the lender.

Some lenders conduct a soft search, which does not leave a visible footprint in the same way as a hard search.

Others conduct a hard search, which is recorded on your credit file and can be visible to other lenders.

GOV.UK and MoneyHelper both advise checking which type of search a lender will perform.

Why This Matters

Suppose you approach several lenders independently and each conducts a hard search.

Multiple hard searches over a short period can potentially affect how lenders view your credit profile.

This doesn’t mean you should avoid comparing mortgage options.

It means you should be strategic about how you compare them.

A broker can help you understand potential lender criteria before unnecessary full applications are submitted.

How Long Does a Mortgage in Principle Take?

The initial MIP process can be relatively quick.

Some lenders allow you to apply online and receive a decision within minutes or hours, provided you have the necessary information.

However, don’t confuse the speed of an MIP with the speed of the full mortgage application.

A full mortgage application requires considerably more information and can involve:

  • Detailed affordability assessment
  • Document verification
  • Credit checks
  • Property valuation
  • Underwriting
  • Legal work

MoneyHelper currently states that a full mortgage application typically takes around 2 to 6 weeks to reach an approval decision, although individual cases vary.

For a broader look at the timeline, read our guide to how long a mortgage takes in the UK.

How Long Does a Mortgage in Principle Last?

An MIP commonly lasts between 30 and 90 days, depending on the lender.

For example, if you receive an MIP on 1 September and it is valid for 90 days, you have approximately three months to use it before needing to renew or obtain another one.

The exact expiry date should be confirmed with the lender.

What Can Change Before It Expires?

Your circumstances could change.

For example:

  • Your income changes
  • You take on new debt
  • Your employment changes
  • Your deposit changes
  • Your credit circumstances change
  • The lender changes its mortgage products or criteria

Therefore, an MIP should never be treated as a permanent guarantee.

What Happens After You Get a Mortgage in Principle?

Once you have your MIP, the next stage is generally property hunting.

Suppose you’ve received:

MIP: £450,000

Deposit: £50,000

Your theoretical maximum property budget could be approximately:

£500,000

But you might decide that a £450,000 property is more appropriate after allowing for transaction costs and maintaining a financial buffer.

Once you find a property and your offer is accepted, you move from the preliminary MIP stage into the full mortgage application.

From MIP to Full Mortgage Application

The lender may request:

  • Proof of income
  • Bank statements
  • Proof of deposit
  • Identification
  • Proof of address
  • Employment information
  • Details of the property
  • Solicitor details

The lender may also arrange a valuation.

MoneyHelper explains that the property itself is assessed during the full mortgage process, and issues with the property’s value or suitability can affect the eventual mortgage offer.

Why a Mortgage in Principle Can Still Be Declined

This is one of the most important things first-time buyers need to understand.

Having an MIP does not guarantee final mortgage approval.

There are two broad areas the lender needs to be satisfied with:

You

and

the property.

Your Circumstances Can Change

If your financial situation changes between receiving the MIP and making the full application, the lender may reassess your affordability.

For example, taking on new borrowing could affect the application.

The Property May Not Meet the Lender’s Criteria

Even if your finances are acceptable, the property can create problems.

MoneyHelper gives examples of properties that some lenders may exclude, including certain homes without working kitchens or bathrooms, some high-rise properties and certain other property types.

This is especially important when buying unusual or non-standard properties.

The Valuation May Be Lower Than Your Purchase Price

Imagine:

Agreed purchase price: £500,000

Lender valuation: £475,000

The lender may calculate its maximum loan against the valuation rather than simply accepting the price you agreed with the seller.

That can create a funding gap.

This is why you should never treat an MIP as permission to bid or offer without considering the property’s characteristics and the lender’s criteria.

Getting a Mortgage in Principle Through a Broker

You can obtain an MIP directly from a lender.

But a mortgage broker can be particularly useful when your circumstances aren’t straightforward.

This may include:

  • Self-employed applicants
  • Applicants with variable income
  • Buyers with a small deposit
  • Applicants with previous credit problems
  • Buyers with multiple income sources
  • Buyers purchasing unusual properties
  • Applicants unsure which lender to approach

GOV.UK notes that using a mortgage broker can be particularly useful where circumstances such as self-employment or a lower credit score may limit the mortgages available.

The FCA also highlights the complexity of the UK mortgage market, where products can have multiple eligibility criteria, features and pricing elements.

The Advantage Isn’t Simply “Getting an MIP”

The real value of specialist advice is understanding which MIP to obtain.

There is little benefit in getting an impressive-looking £500,000 MIP from a lender whose criteria won’t accept the property you ultimately want to buy.

A better approach is:

Understand your circumstances → identify suitable lenders → obtain an appropriate MIP → search for property → make an offer → submit the full application

That creates a more controlled mortgage journey.

Your Next Steps

If you’re preparing to buy a property in the UK, use this sequence:

  1. Calculate your deposit.
  2. Review your income and monthly expenditure.
  3. Check your credit report.
  4. Gather your key financial information.
  5. Decide whether to approach a lender directly or use a broker.
  6. Check whether the MIP will involve a soft or hard credit search.
  7. Obtain your mortgage in principle.
  8. Set a realistic property budget.
  9. Start viewing properties within that budget.
  10. Once your offer is accepted, progress to the full mortgage application.

If you’re buying in London, you may also want to read our guide to first-time buyer mortgages in London to understand how deposit size, affordability and additional purchase costs affect your overall buying strategy.

If you’re ready to understand your mortgage options before making an offer, speaking to a London mortgage broker can help you assess your circumstances and identify an appropriate route to finance.

Mastering the Mortgage in Principle Process

A mortgage in principle is one of the simplest ways to turn your property search from guesswork into a more realistic financial plan.

It tells you what a lender may be prepared to lend based on the information available at that stage.

But remember the distinction:

MIP ≠ mortgage offer.

The final mortgage decision still depends on a full assessment of your financial circumstances and the property you want to purchase.

For first-time buyers, the smartest approach is therefore not to chase the largest possible MIP.

It is to establish a realistic borrowing range, understand the costs of buying, prepare your documentation and identify mortgage options that fit your circumstances.

That preparation can make the difference between finding a property you want and being financially ready to complete the purchase.

If you’re buying in London and aren’t sure how much you can realistically borrow, getting professional mortgage advice before making an offer can help you approach the market with greater confidence.

Frequently Asked Questions

What is a mortgage in principle?

A mortgage in principle is an indication from a lender of how much it may be prepared to lend you based on information about your financial circumstances.

It is not a formal mortgage offer or guarantee of approval.

Is a mortgage in principle the same as an Agreement in Principle?

Generally, yes.

Mortgage in Principle, Agreement in Principle and Decision in Principle are different terms lenders commonly use for the same preliminary indication of potential borrowing.

Do I need a mortgage in principle to buy a house?

No, it is not a legal requirement.

However, having one can be useful when making an offer because it gives you a clearer idea of your borrowing capacity and can demonstrate to sellers that you are serious about buying.

How much does a mortgage in principle cost?

Many lenders provide an MIP free of charge.

However, if you use a mortgage broker, check whether the broker charges a fee for their service. MoneyHelper notes that some brokers may charge for obtaining or arranging an MIP.

How long does a mortgage in principle last?

It commonly lasts between 30 and 90 days, although the exact period varies by lender.

Does getting an MIP hurt my credit score?

It depends on the credit search used.

Some lenders use a soft search, while others use a hard search. A hard search is recorded on your credit file and multiple hard searches over a short period can potentially be negative for your credit profile.

Can I get a mortgage in principle with bad credit?

Potentially.

The availability of mortgage products will depend on the nature, severity and recency of your credit issues and the lender’s criteria.

If you have bad credit, it can be particularly useful to understand your options before submitting multiple applications.

Read our guide to bad credit mortgages in London for more information.

Can I get a mortgage in principle if I am self-employed?

Yes.

Self-employed applicants can obtain MIPs, although lenders may require additional evidence of income, such as business accounts and tax documentation. Requirements vary between lenders.

Can a mortgage in principle be rejected?

Yes.

A lender may decline to provide an MIP based on the information supplied.

Even if you receive an MIP, however, your final mortgage application can still be declined after the lender carries out more detailed financial and property checks.

Can I make an offer without a mortgage in principle?

Yes.

You can make an offer without an MIP, but having one can strengthen your position and give you a clearer understanding of your potential borrowing capacity.

In a competitive market, an estate agent may also ask to see evidence of your mortgage position.

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