Mortgage in Principle Explained

What Is a Mortgage in Principle?

A mortgage in principle is a lender's initial assessment of how much they'd be willing to lend you, based on the information you provide. The numbers tell us it's essentially a "pre-approval"—not a guarantee, but a strong indication that you'd likely qualify for a mortgage up to a certain amount.

Here's what that actually means in practical terms: you fill out an application with your income, outgoings, and deposit details. The lender runs some basic checks and tells you the maximum they'd consider lending. This gives you a budget to work with when searching for properties.

What an MIP Tells You

An MIP confirms several important things:

• The maximum amount this lender would likely offer you
• That your basic financial situation passes initial scrutiny
• That you don't have any obvious credit issues blocking approval

What an MIP Doesn't Guarantee

It's important to be clear about the limitations. An MIP is not a mortgage offer. It doesn't guarantee:

• That you'll actually get the mortgage when you formally apply
• That the property you choose will be acceptable to the lender
• That your circumstances won't change between MIP and application
• That the rates quoted will still be available later

Per FCA affordability assessment data, the honest answer is that around 10-15% of MIPs don't convert to full mortgage offers. That's not a reason to skip getting one—it's a reason to understand what it is and isn't.

Why You Need a Mortgage in Principle

The maths on why an MIP matters is straightforward. The average property search takes 3-6 months. During that time, you'll view perhaps 10-20 properties and make 2-3 offers before one is accepted. Without an MIP, you're doing all this without knowing if you can actually afford what you're looking at. Use our affordability calculator to establish a rough budget before applying.

Confirms Your Budget

The most fundamental reason: an MIP tells you what you can actually borrow. Data on buyer behaviour shows one of the most common mistakes is searching based on rough calculations rather than confirmed figures. An MIP removes the guesswork.

If you think you can borrow £300,000 but it turns out you can only get £270,000, that changes everything—from locations you can consider to property types you can afford.

Estate Agents Expect It

Per MoneyHelper guidance, the data shows a different story from how things worked a decade ago. Today, most estate agents will ask if you have an MIP before accepting an offer. Some won't even arrange viewings without one.

From the agent's perspective, this makes sense. They're trying to filter serious buyers from casual browsers. An MIP demonstrates you've done the preparation work and can actually proceed if you find a property.

Speeds Up the Process

Once your offer is accepted, the clock starts ticking. Sellers get nervous during long transactions. Having an MIP in place means you can move to full mortgage application immediately, shaving days or even weeks off your timeline. Learn more about how to apply for a mortgage after your offer is accepted.

When to Get a Mortgage in Principle

Timing matters. Get your MIP too early, and it might expire before you find a property. Get it too late, and you'll waste time viewing homes you can't afford—or lose out because you can't move fast enough on an offer.

The Ideal Timing

Get your MIP when you're ready to start serious searching—typically after you've:

• Saved enough deposit (or know exactly when you will)
• Checked your credit report and fixed any issues
• Gathered basic documents (payslips, bank statements)
• Decided roughly where and what you want to buy

For most buyers, this means getting your MIP 1-2 weeks before you start booking viewings.

Validity Periods

Most MIPs last 30-90 days, depending on the lender. Some last up to 6 months. If yours expires before you find a property, you'll need to renew it—which is straightforward if your circumstances haven't changed.

Renewing Your MIP

If your MIP expires, the renewal process is usually quick. The lender already has your details; they just need to confirm nothing's changed. However, if interest rates have moved significantly, the amount you can borrow might be different.

How to Get a Mortgage in Principle

You have two main routes: go directly to lenders, or use a mortgage broker. Both work, but they have different advantages.

Direct with Lenders

You can apply for MIPs directly through banks and building societies. Most have online applications that take 15-30 minutes. The advantage is speed and simplicity. The disadvantage is that each application only tells you about that one lender's criteria.

Through a Mortgage Broker

A broker can assess your situation and suggest which lenders are most likely to approve you—potentially checking multiple options with a single application. This is particularly valuable if you have complex income or any credit concerns.

Online vs In-Person

Most MIPs are now done online. It's faster and more convenient. However, if your situation is complicated—self-employment, multiple income sources, past credit issues—a phone or in-person conversation can help ensure the lender understands your full picture.

Step-by-Step Process

1. Choose your route — Direct lender or broker
2. Gather basic information — Income, employment, deposit, outgoings
3. Complete the application — Online form or phone call
4. Wait for the result — Usually instant to 24 hours
5. Receive your MIP certificate — Keep this for estate agents

What You'll Need

The documentation requirements for an MIP are lighter than a full mortgage application, but you'll still need:

Income Details

• Your annual salary (or average earnings if variable)
• Any additional income (bonuses, overtime, second job)
• Partner's income if applying jointly

Employment Information

• Employer name and address
• How long you've been employed there
• Your job title and contract type

Deposit Information

• How much deposit you have
• Where it's coming from (savings, gift, etc.)

Outgoings and Commitments

• Existing debts (loans, credit cards, car finance)
• Regular financial commitments
• Childcare costs or maintenance payments

ID Verification

Most lenders will verify your identity electronically. You'll typically need:

• Your current address history (last 3 years)
• National Insurance number

Credit Check Impact

This is where many buyers get confused—and rightly concerned. There are two types of credit checks, and they have very different implications.

Soft vs Hard Searches

According to FCA credit guidance, a soft search (also called a quotation search) doesn't leave a mark on your credit file that other lenders can see. It's essentially invisible to future lenders.

A hard search (also called an application search) does leave a mark. Multiple hard searches in a short period can temporarily lower your credit score.

Which Lenders Do Which

Per FCA regulation, the picture has improved in recent years. Most major lenders now use soft searches for MIPs, reserving hard searches for the full application. However, this isn't universal.

Before applying, ask the lender directly: "Does this MIP application involve a soft or hard credit search?" If they can't answer clearly, consider that a yellow flag.

Protecting Your Credit Score

If you're concerned about credit impact:

• Use lenders that explicitly offer soft-search MIPs
• Consider using a broker who can check eligibility across multiple lenders
• Avoid applying to multiple lenders doing hard searches
• Space out any hard-search applications by a few weeks if possible

What Happens Next

Your MIP is a tool, not a destination. Here's how to use it effectively.

Using Your MIP

When you find a property you want to make an offer on, you'll typically need to:

• Provide a copy of your MIP to the estate agent
• Confirm the MIP covers the offer amount you're making
• Be ready to move quickly to full application if your offer is accepted

When to Apply Formally

The full mortgage application happens after your offer is accepted. At that point, you'll:

• Provide comprehensive documentation
• The lender will conduct a property valuation
• Full underwriting and affordability assessment
• Receive a binding mortgage offer (if approved)

From MIP to Mortgage Offer

The journey typically looks like this:

1. MIP obtained — You're ready to search
2. Property found — Make offer with MIP evidence
3. Offer accepted — Submit full mortgage application
4. Valuation completed — Lender assesses the property
5. Underwriting — Lender reviews all documentation
6. Mortgage offer issued — Legally binding commitment

This process typically takes 2-4 weeks from offer acceptance to mortgage offer.

Does an MIP guarantee I'll get a mortgage?

No. An MIP is an indication, not a guarantee. The full application involves more detailed checks, including a property valuation. Approximately 10-15% of MIPs don't convert to full offers, usually because circumstances change or property issues arise.

Can I get multiple MIPs from different lenders?

Yes, but be strategic about it. If lenders use soft searches, multiple MIPs won't affect your credit score. If they use hard searches, multiple applications in a short period could temporarily impact your score. A broker can often check multiple lenders with one search.

What if my MIP application is rejected?

Don't panic. A rejection means that particular lender, at that moment, doesn't think you fit their criteria. Different lenders have different criteria. A broker can help identify lenders more suited to your situation. Also check your credit report for any surprises that might be causing issues.

How long does an MIP last?

Typically 30-90 days, though some last up to 6 months. Check with your specific lender. If it expires before you find a property, you can usually renew it quickly, though the amount offered might change if your circumstances or interest rates have shifted.

Do I need an MIP for every property I view?

No. One MIP works for any property within that borrowing amount. You don't need a new MIP for each viewing—just ensure the property price is within your approved borrowing range plus your deposit.

Next Steps

With your MIP in hand, you're ready to start your property search properly. You know what you can afford, and you can prove it to estate agents.

Understanding the different types of mortgages available will help you make better decisions when you move from MIP to full application.