Building Society Mortgage in Principle: Application Guide

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Independent UK Mortgage Application Guide · 2026

Building Society Mortgage in Principle: Application Guide

A building society mortgage in principle gives you an initial indication of how much a mortgage lender may be prepared to lend. It helps you set a property budget and can show an estate agent that you have taken an early step towards arranging finance.

It is not a guaranteed mortgage offer. The lender still needs to assess your full application, supporting documents, credit information and the property before agreeing to lend.

This guide explains how to apply through UK building societies, what information you need, which lenders currently use soft credit checks, how long the decision lasts and what to do if your application is accepted, referred, declined or expires.

How to Apply Compare Building Societies What You Need
Independent information: Building-society.org is not a mortgage lender or adviser. Do not submit passport numbers, bank login details, payslips or financial documents to this website. Apply through the official building society or an appropriately authorised mortgage intermediary.

Editorial review: 13 October 2026. Lender-specific Decision in Principle details have been checked against published building society guidance. Eligibility rules, credit-search practices and validity periods may change.

Mortgage in Principle: Quick Answers

What is it? An initial lending decision based on information about your circumstances and the lender’s preliminary checks.
Other names Agreement in Principle (AIP), Decision in Principle (DIP) or Mortgage in Principle (MIP).
How long does it take? Some online systems provide a result within minutes. Nationwide currently estimates around 20 minutes to complete its DIP.
How long is it valid? Often 30–90 days. Nationwide and Yorkshire Building Society currently publish 90 days; Skipton specifies 30 days to complete the full application.
Does it cost money? A DIP is usually free when obtained directly from a lender. Some intermediaries charge advice or administration fees.
Will it affect credit? Not necessarily. Nationwide, YBS and Skipton currently describe soft-search DIP processes.
Do you need a property? Not usually. Many buyers obtain a DIP before finding a property.
Does it guarantee a mortgage? No. Formal underwriting, affordability, credit checks and property assessment still apply.
Best starting point: calculate your deposit and realistic household budget, then choose a building society whose lending criteria fit your circumstances. Check its credit-search policy before submitting the application.

What Is a Building Society Mortgage in Principle?

A Mortgage in Principle is a preliminary indication from a lender that it may be willing to lend you a certain amount based on the information supplied and its initial assessment.

UK building societies commonly use the terms Decision in Principle or Agreement in Principle. These terms describe broadly the same stage of the mortgage process.

The decision is useful because it provides a provisional borrowing figure before you commit to a particular property.

What a DIP can do

  • Provide an initial borrowing estimate.
  • Help you establish a property-search budget.
  • Demonstrate initial financial preparation to an estate agent.
  • Identify potential eligibility issues before a full application.
  • Provide a route into the lender’s formal application process.

What a DIP cannot do

  • Guarantee final mortgage approval.
  • Reserve a particular mortgage rate automatically.
  • Confirm the property’s value or suitability.
  • Replace detailed affordability checks.
  • Guarantee the lender will accept your supporting documents.
  • Commit the lender to provide funds.
Practical example: a building society might issue a DIP indicating possible borrowing of £220,000. That does not mean it will necessarily lend £220,000 on every property or approve the amount after checking all your documents.

Do Estate Agents Require a Mortgage in Principle?

A DIP is not a legal requirement before making an offer on a property. However, estate agents may request one to establish that you are in a position to proceed.

This is particularly common when several buyers are interested in the same home.

An estate agent may also request proof of your deposit. A DIP does not replace evidence that your deposit funds are available.

Independent UK guidanceMoneyHelper: What Happens When You Get a Mortgage in Principle?

After opening this link:

  1. Read the explanation of a Mortgage in Principle and why buyers obtain one.
  2. Check whether you need one before viewing or offering on a home.
  3. Review the typical information required.
  4. Understand the difference between an initial decision and a full mortgage offer.
  5. Check the lender’s own terms before applying.

How to Apply for a Building Society Mortgage in Principle

Many UK building societies offer a direct online route. Others may use telephone advisers, branch-based appointments or mortgage intermediaries for particular circumstances.

  1. Choose your mortgage purpose. Identify whether you are a first-time buyer, home mover, remortgager or existing borrower seeking additional borrowing.
  2. Estimate your property budget. Work out your available deposit, other buying costs and a manageable monthly repayment.
  3. Check the lender’s eligibility conditions. Review age, residency, employment, property and borrowing requirements.
  4. Prepare personal information. Have your legal name, date of birth, contact details and previous addresses available.
  5. Prepare income and expenditure details. Include employment earnings, self-employed income, regular commitments, debts and relevant household spending.
  6. Open the official DIP application. Use the building society’s website or an authorised intermediary.
  7. Answer the questions accurately. Do not overstate income, understate borrowing or omit people who will be included in the mortgage.
  8. Review the credit-search information. Confirm whether the initial check is soft or hard before continuing.
  9. Submit the request. The lender may give an immediate result or refer the case for additional checks.
  10. Keep the confirmation. If approved, save the certificate, reference, amount, expiry date and instructions for continuing.
Important: a lender’s decision may change if the income, deposit, debts, applicants or property details change between the DIP and full application.

Building Society Mortgage in Principle: Compare Official Application Routes

There is no single UK building society DIP system. Each lender applies its own eligibility, borrowing and application requirements.

The following comparison focuses on confirmed guidance from Nationwide, Yorkshire Building Society and Skipton rather than unverified offers or advertised interest rates.

Building society
Current published DIP information
Credit and validity
Nationwide Building Society
Online DIP route; estimated application time around 20 minutes. Accepted online applicants receive a PDF certificate and access to Mortgage Hub.
Soft credit check; 90-day validity.
Yorkshire Building Society
DIP process for qualifying mortgage applicants, including initial income, expenditure and credit information.
Soft credit check; 90-day validity under current guidance.
Skipton Building Society
Affordability assessment followed by a DIP, with advice and full application routes.
Soft credit check; 30 days to complete a full application.
How to choose: validity and soft credit checks are useful, but lender suitability matters more. Consider the property type, loan-to-value, employment income, credit circumstances and products available when you apply.

1. Nationwide Building Society Decision in Principle

Nationwide currently says its online DIP takes around 20 minutes, lasts 90 days and uses a soft credit check.

If accepted, an online applicant receives a PDF certificate by email and a route into Nationwide’s Mortgage Hub.

Official Nationwide applicationGet a Nationwide Decision in Principle

After opening this link:

  1. Read the DIP eligibility and preparation information.
  2. Select the mortgage purpose that applies to you.
  3. Prepare income, deposit, credit and regular spending information.
  4. Continue to Nationwide’s secure DIP process.
  5. Review the result and save the certificate if accepted.
  6. Keep the confirmation email because its Mortgage Hub link is used to continue the application.

2. Yorkshire Building Society Decision in Principle

Yorkshire Building Society explains that its DIP is an initial indication of mortgage eligibility and uses a soft credit check.

YBS currently states that its DIP is valid for 90 days, provided the applicant’s circumstances remain consistent with the information supplied.

Official YBS guidanceYorkshire Building Society: What Is a Decision in Principle?

After opening this link:

  1. Read how YBS uses income, outgoings and credit information.
  2. Check the current validity period.
  3. Review the soft-search explanation.
  4. Use YBS’s mortgage application navigation to find the relevant DIP route.
  5. Check whether your mortgage circumstances qualify for its online application service.

3. Skipton Building Society Decision in Principle

Skipton’s mortgage guidance places an affordability calculation before the DIP. It currently uses a soft credit search at the DIP stage.

Skipton specifies that applicants have 30 days to complete a full mortgage application once they obtain an accepted DIP and have an offer accepted on a property.

Official Skipton applicationSkipton: Get a Decision in Principle

After opening this link:

  1. Read the affordability calculator instructions.
  2. Enter accurate income and outgoings.
  3. Review the borrowing estimate.
  4. Continue to the DIP stage where eligible.
  5. Check the result and the period available to submit a full application.
  6. Use Skipton’s mortgage adviser route if you need help proceeding.
No mortgage rate is secured just because a DIP is accepted. A lender may change or withdraw products while you are house hunting. Check rate availability and any fee needed to secure a specific deal at the full-application stage.

What Information and Documents Do You Need?

The initial DIP often requires information rather than uploading a full pack of documents. However, having supporting records ready helps you provide accurate answers.

Personal details
  • Full legal name.
  • Date of birth.
  • Current address.
  • Previous address history.
  • Contact information.
Income details
  • Employment income.
  • Bonuses and commission where accepted.
  • Self-employed earnings.
  • Other qualifying income.
  • Joint applicant income.
Monthly spending
  • Credit card commitments.
  • Personal loans.
  • Car finance.
  • Childcare.
  • Maintenance commitments.
  • Other recurring expenditure.
Deposit information
  • Expected deposit.
  • Source of savings.
  • Gifted funds if applicable.
  • Existing property equity.
  • Estimated property price.
Employed applicants
  • Recent payslips.
  • P60 if requested.
  • Employment and contract details.
  • Recent bank statements.
Self-employed applicants
  • SA302 tax calculations.
  • Tax year overviews.
  • Business accounts.
  • Accountant details if relevant.
  • Recent bank statements.
Preparation tip: Yorkshire Building Society says applicants should prepare three years of address history. Many lenders request similar information, but always follow the exact requirements of the society you choose.

Are Documents Required Before a DIP?

Not always. Some systems provide an initial decision from the information you enter and their electronic checks.

The full mortgage application generally requires more formal evidence, such as payslips, statements, identification and deposit documents.

Official mortgage preparationMoneyHelper: Mortgage Application Process and Documents

After opening this link:

  1. Locate the mortgage application preparation section.
  2. Read the list of typical identity and income documents.
  3. Check requirements for your employment situation.
  4. Prepare evidence of your deposit and its source.
  5. Keep relevant files ready for secure submission if the lender requests them.

Does a Mortgage in Principle Affect Your Credit Score?

It depends on the lender and its process. A soft search and a hard search have different implications.

Soft Credit Search

  • Used by many lenders at the initial DIP stage.
  • Does not affect your credit score.
  • Not visible to other lenders as a borrowing application.
  • Can help establish initial eligibility.

Nationwide, Yorkshire Building Society and Skipton currently state that their standard DIP processes use soft checks.

Hard Credit Search

  • Leaves a visible credit-application search record.
  • May be used at the full mortgage application stage.
  • Some lenders may use one earlier in the process.
  • Multiple hard searches close together can affect a credit assessment.

Check the exact search type before submitting an application.

Do not assume every DIP is soft-search only. Ask the lender before proceeding if its website does not explain the credit check. An initial soft check does not mean the full application will avoid a hard check.

Can You Get More Than One Mortgage in Principle?

Yes. It is possible to obtain decisions from more than one lender.

However, there is little benefit in submitting numerous DIP requests without checking whether those lenders accept your circumstances. Compare the criteria and credit-search policies first.

Independent credit guidanceMoneyHelper: Credit Checks and Declined Mortgage Applications

After opening this link:

  1. Read the explanation of soft and hard searches.
  2. Review why repeated credit applications may create difficulties.
  3. Check what to do if the lender declines the initial application.
  4. Consider correcting credit-record errors before another formal application.

How Much Could a Building Society Lend You?

A DIP borrowing amount depends on much more than annual salary. Building societies examine household income, spending commitments, loan term and their lending criteria.

The amount displayed is a preliminary assessment, not a promise that the monthly repayments will be suitable for your household.

Simple Property Budget Example

Assume a buyer has:

Available deposit £30,000
Illustrative DIP £220,000
Combined amount £250,000
£220,000 + £30,000 = £250,000

The buyer has an illustrative total of £250,000 before transaction costs and any separate cash reserve.

This is a budget example, not a lender offer. If some of the £30,000 is needed for legal fees, survey costs, moving expenses or property transaction tax, the practical purchase budget will be lower.

Do Not Borrow the Maximum Automatically

A lender’s maximum indication may be higher than the amount you personally feel comfortable repaying.

Consider how your budget would cope with an increase in mortgage interest rates, a period of lower income, higher childcare costs or unexpected home repairs.

Check your comfortable monthly repayment.
Allow for home maintenance.
Include insurance costs.
Keep an emergency reserve where possible.
Account for buying and moving costs.
Understand when the initial rate ends.

Independent calculatorMoneyHelper: Mortgage Affordability Guidance

After opening this link:

  1. Read how lenders consider income and expenditure.
  2. Review the difference between a borrowing estimate and an affordable repayment.
  3. Prepare your expected deposit and household costs.
  4. Use the linked affordability tools where appropriate.
  5. Compare the results with the building society’s own assessment.

How Long Does a Building Society Mortgage in Principle Last?

Many DIPs remain valid for around 30 to 90 days. There is no single universal validity period.

Lender
Published period
What happens next
Nationwide
90 days
Eligible applicants can renew through Mortgage Hub and confirm their details.
Yorkshire Building Society
90 days
An updated decision may be required if the previous one expires or circumstances change.
Skipton
30 days to complete a full application
Check the next-step requirements and arrange the mortgage appointment where needed.

What if Your DIP Expires Before You Find a Home?

An expired DIP does not automatically mean the lender has rejected you. It means the previous preliminary decision is outside its stated validity period.

You may need to renew it, reconfirm your information or complete another eligibility assessment.

Official renewal routeNationwide: Renew an Expired Decision in Principle

After opening this link:

  1. Find the section about an expired DIP.
  2. Use the Mortgage Hub link from your previous confirmation email.
  3. Confirm whether your income, spending and other details have changed.
  4. Follow the current renewal process.
  5. Save the updated confirmation and expiry date if the renewal is accepted.
Changes matter: if you change jobs, take out a personal loan, reduce your working hours or use part of your deposit, tell the lender. A previous DIP may no longer reflect your financial circumstances.

Mortgage in Principle Accepted, Referred or Declined: What Happens?

Not every lender responds with the same decision categories. An application can be accepted immediately, referred for further consideration or declined.

Accepted The lender has provisionally indicated that it may be willing to lend the amount shown, subject to further checks.
Referred The system may need additional evidence or manual review. This is not necessarily a rejection.
Declined The initial assessment has not met the lender’s requirements or sufficient information could not be verified.

If Your Mortgage in Principle Is Declined

Do not assume that every other building society will reject you. Lenders have different income, property, credit and affordability requirements.

However, applying repeatedly without understanding the issue may create unnecessary complications.

  1. Check the details submitted for mistakes.
  2. Ask the lender whether it can explain the outcome.
  3. Check your credit records for inaccuracies.
  4. Review affordability and existing borrowing commitments.
  5. Consider whether a different lender’s criteria genuinely fit your circumstances.
  6. Discuss complex cases with an authorised mortgage adviser.
Useful distinction: a lower-than-expected borrowing figure is not necessarily a declined application. It may mean the lender’s affordability calculation permits a smaller loan.

What Happens After You Receive a Mortgage in Principle?

Once you have an accepted DIP, you can continue looking for a suitable property within your realistic budget.

The next steps depend on whether you are buying a first home, moving home or remortgaging.

For a Property Purchase

  1. Search for homes that fit your budget and property requirements.
  2. Give the estate agent the DIP certificate if requested.
  3. Make an offer on the property you want to buy.
  4. If the offer is accepted, instruct a conveyancer and follow the lender’s full-application process.
  5. Submit the required income, identity and deposit documents.
  6. Allow the lender to assess the property and complete underwriting.
  7. Review the formal mortgage offer if approved.
  8. Proceed through conveyancing, exchange of contracts where applicable and completion.

For a Remortgage

If you are changing mortgage lender, the application normally requires an assessment of your current borrowing, property value, income and financial commitments.

Check whether your existing deal has an Early Repayment Charge, and account for valuation, legal and product fees.

DIP vs Full Mortgage Offer

Feature
Mortgage in Principle
Full mortgage offer
Purpose
Initial borrowing indication.
Formal mortgage lending approval subject to offer conditions.
Checks
Preliminary financial and credit checks.
Detailed income, credit, affordability and property checks.
Property
Specific property often not required.
Specific property and valuation normally required.
Guarantee
Not guaranteed borrowing.
Formal offer, still subject to its terms and conditions.
Property warning: a lender can accept your initial financial circumstances but later decline a particular property because of construction type, condition, valuation, lease terms or another lending-policy issue.

Mortgage in Principle Applications With Special Circumstances

Not every applicant has a straightforward permanent salary and a conventional deposit. If your circumstances are unusual, check the lending policy before starting an automated application.

Self-employed applicants The lender may use tax calculations, company accounts or other accepted income evidence. The number of years required varies.
Contractors Some lenders accept qualifying day-rate or fixed-term income arrangements rather than relying entirely on traditional accounts.
Fixed-term employment The lender may review contract duration, renewal prospects and previous employment history.
Joint applications Both applicants’ income, borrowing and expenditure can affect the assessment. Joint applicants may also be jointly liable for the mortgage.
Gifted deposits The lender may need evidence of the source of the gift, the donor’s identity and confirmation of whether repayment is expected.
Previous credit difficulties Historic missed payments, defaults or other adverse credit events may require closer consideration under individual lender rules.
Later-life borrowing Age, income during retirement, mortgage term and available product types can affect the lender’s decision.
Shared ownership or new builds Specific property and scheme criteria may apply, so check eligibility before relying on a general DIP figure.
Important: do not change an application answer simply to get through an online eligibility screen. If the system does not fit your circumstances, use the lender’s telephone or advised route instead.

Common Mortgage in Principle Mistakes to Avoid

Overstating income Only enter earnings that the lender permits under its rules. Bonuses, overtime and self-employed income may be treated differently.
Leaving out borrowing Credit cards, loans, car finance and other commitments can affect the lender’s decision.
Ignoring the expiry date Your DIP may expire while you search for a property.
Assuming the rate is fixed A DIP does not automatically reserve a mortgage product or interest rate.
Using every available DIP Multiple applications are not always necessary. Check the lender’s criteria and credit-search policy first.
Spending the entire deposit Legal fees, property taxes, surveys, moving costs and emergency reserves also need consideration.
Changing finances before completion New borrowing, job changes or missed payments can affect a later lending assessment.
Assuming approval is final The lender must still be satisfied with the property, supporting evidence and full application.
Before submitting: recheck the spelling of names, address history, income figures, monthly commitments, deposit amount and proposed loan term. Correcting information early can prevent avoidable delays.

When Is the Best Time to Get a Mortgage in Principle?

For many buyers, the most useful time is when the deposit is taking shape, the household budget is understood and property viewings are about to begin.

Applying too early may mean the decision expires before you need it. Applying only after a seller accepts an offer can leave you scrambling to establish borrowing eligibility.

You have a realistic deposit estimate.
You understand regular household spending.
You have checked significant credit commitments.
You are ready to start viewing properties.
You know the borrowing purpose.
You are prepared for the next application stage.

Property purchase procedures vary across England, Wales, Scotland and Northern Ireland. A DIP is a UK-wide mortgage concept, but conveyancing, transaction taxes and the legal steps for purchasing a home differ by jurisdiction.

Should You Apply Directly or Through a Mortgage Broker?

Applying Directly

  • Use the building society’s official application process.
  • Check that it accepts your mortgage circumstances.
  • Review its own lending range and requirements.
  • Ask whether an adviser will provide a recommendation or the route is execution-only.

Using a Mortgage Intermediary

  • May help compare criteria across several lenders.
  • Useful when income, credit or property circumstances are complex.
  • Can explain the documentation needed.
  • Check the intermediary’s lender panel, advice status and any fees before proceeding.

Official regulatorFCA: Check Whether a Mortgage Adviser Is Authorised

After opening this link:

  1. Read the FCA’s guidance about checking financial firms.
  2. Open the Firm Checker or Financial Services Register.
  3. Search for the adviser’s registered business.
  4. Check relevant permissions or appointed-representative details.
  5. Verify contact details independently before paying fees or sharing financial documents.

Related UK Building Society Mortgage Guides

These related guides provide further information about building society borrowing, mortgage rates and application requirements.

Nationwide Building Society: Mortgages, Savings and Help Nationwide Building Society Mortgage Rates and Remortgage Guide Yorkshire Building Society: Mortgages and Member Services Yorkshire Building Society Mortgage Rates and Deals

Official Resources Used for This Guide

Use these sources to check the current application process, validity period, credit-search policy and mortgage requirements.

Nationwide Decision in Principle Yorkshire Building Society DIP Guidance Skipton Decision in Principle MoneyHelper: Mortgage in Principle Explained MoneyHelper: Mortgage Application Process MoneyHelper: Declined Applications FCA Authorisation Checker
Source-use guidance: detailed instructions explaining what to do after opening each major official link appear in the relevant sections above. Follow current official information if it differs from older guides.

Independent Financial Information and Accuracy Notice

Building-society.org is an independent educational website. It is not Nationwide Building Society, Yorkshire Building Society, Skipton Building Society, the Financial Conduct Authority or a regulated mortgage intermediary.

This guide does not provide personalised mortgage advice, approve applications, issue Decisions in Principle or guarantee borrowing.

Mortgage lending depends on individual circumstances, underwriting requirements, affordability, credit information and the property used as security.

Mortgage risk: your home may be repossessed if you do not keep up repayments on your mortgage. Review the interest rate, APRC, product fees, repayment term, Early Repayment Charges and other conditions before accepting a mortgage offer.

Editorial accuracy review: 13 October 2026. The lender-specific DIP durations and credit-search explanations in this guide reflect the referenced published sources. Future criteria and product changes should be confirmed directly with the lender.

Building Society Mortgage in Principle FAQs

1. What is a building society mortgage in principle?

A Mortgage in Principle is an initial indication of how much a building society may be prepared to lend based on preliminary financial and credit checks. It is not a guaranteed mortgage offer.

2. How do I apply for a building society mortgage in principle?

Choose a suitable building society, open its official DIP application, enter accurate personal, income, expenditure and deposit information, review the credit-search terms and submit the request. Save the certificate if accepted.

3. Does getting a mortgage in principle affect my credit score?

It depends on the lender. Nationwide, Yorkshire Building Society and Skipton currently state that their standard DIP processes use soft credit checks that do not affect credit scores. Other lenders may use different checks.

4. How long does a building society mortgage in principle last?

Many are valid for 30 to 90 days. Nationwide and Yorkshire Building Society currently state 90 days. Skipton specifies 30 days to complete a full application after its DIP process.

5. Can I get a mortgage in principle without finding a house?

Yes. Many UK lenders allow buyers to obtain a DIP before choosing a property. It can help establish a realistic price range and demonstrate preparation to estate agents.

6. Is a mortgage in principle the same as a mortgage offer?

No. A Mortgage in Principle is a preliminary assessment. A formal mortgage offer follows the lender’s full review of the application, financial evidence, credit information and property, and remains subject to the offer’s terms.

7. Can I have more than one mortgage in principle?

Yes. You can request DIPs from different lenders, but check their credit-search policies before applying. Multiple applications are not necessarily useful if the lenders’ criteria do not fit your circumstances.

8. What happens if my mortgage in principle expires?

You may need to renew the decision or submit updated information. Nationwide currently provides an online renewal route through its Mortgage Hub for eligible applicants. The lender may reassess your circumstances.

9. Why might a mortgage in principle be declined?

Possible reasons include affordability, credit information, income eligibility, incorrect details or a mismatch with the lender’s requirements. Ask for clarification where possible and correct any errors before applying again.

10. Is Building-society.org an official mortgage application website?

No. Building-society.org is an independent informational website. It cannot issue mortgage decisions or process applications. Apply through the building society’s official website or an appropriately authorised mortgage intermediary.

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