A mortgage in principle is the first concrete step towards buying a home. Before you start seriously viewing properties — and certainly before you make an offer — getting an MIP tells you how much a lender would be prepared to lend, shows vendors and estate agents you are financially ready, and helps you focus your search on properties you can genuinely afford.
This guide explains what a mortgage in principle is, how to get one, whether it affects your credit, and what it does and does not guarantee.
What Is a Mortgage in Principle?
A mortgage in principle (MIP) is a statement from a mortgage lender saying, in principle, they would be willing to lend you a certain amount. It is based on preliminary information about:
- Your income and employment status
- Your credit profile (soft or hard search)
- Your deposit amount
- Basic outgoings
It is not a firm mortgage offer, a binding commitment, or a guarantee. The actual mortgage offer comes later, after a full application, detailed affordability assessment, and property valuation.
The Many Names for the Same Document
Lenders use different terms, but they all mean the same thing:
| Term | Short Form | Used By |
|---|---|---|
| Mortgage in principle | MIP | Common term, wide usage |
| Agreement in principle | AIP | Nationwide, Halifax, others |
| Decision in principle | DIP | NatWest, Barclays, others |
| Approval in principle | — | Some smaller lenders |
If you see any of these terms, they refer to the same document.
Why Get a Mortgage in Principle?
For House-Hunting
- Confirms your budget before you waste time viewing properties you cannot afford
- Required by most estate agents before they take an offer seriously
- Puts you in a stronger position in competitive markets where sellers prioritise proceedable buyers
For Yourself
- Clarifies what you can realistically borrow
- Identifies any credit issues early — before you have emotionally invested in a property
- Gives you time to fix problems (errors on credit file, improving score) before a full application
Soft Search vs Hard Search: The Credit Score Question
This is one of the most important questions to ask before getting a mortgage in principle.
Soft Credit Search
- Leaves no visible mark on your credit file
- Other lenders cannot see it
- Does not affect your credit score
- You can apply for several soft-search MIPs without any credit impact
Hard Credit Search
- Leaves a footprint visible to other lenders for 12 months
- Can temporarily reduce your credit score slightly
- Multiple hard searches in a short period may signal credit-seeking behaviour to lenders
- One hard search is unlikely to cause significant damage; several in 30 days can
What to ask: “Do you use a soft or hard search for the mortgage in principle?”
Most lenders now offer soft searches at MIP stage and move to hard searches only at full application. Some still use hard searches — it is worth checking and potentially choosing a different lender or broker if so.
Who Provides a Mortgage in Principle?
Three routes:
Direct with a Lender
Apply for an MIP directly with a bank or building society. Takes 10–30 minutes online. You are limited to that lender’s products and criteria.
Via a Mortgage Broker
A broker searches across multiple lenders and can identify the most appropriate lender for your circumstances before you apply. Brokers also know which lenders use soft searches.
Some brokers charge fees; others are fee-free and are paid by commission from lenders.
Via a Price Comparison Website
Some comparison sites partner with brokers or lenders to offer an indicative MIP. Quality varies — a direct broker conversation is usually more reliable.
What You Need to Apply
Most MIP applications ask for:
| Information | Detail |
|---|---|
| Personal details | Name, date of birth, address history (3 years) |
| Income | Salary, self-employment income, benefits, other income |
| Employment | Employed, self-employed, retired |
| Deposit | Amount and source |
| Property value | Approximate amount you are looking to spend |
| Credit commitments | Existing loans, credit cards, car finance |
| Basic outgoings | Monthly rent/mortgage, dependants |
You do not need the property address yet — the MIP is independent of a specific property.
How Much Will You Be Offered?
Lenders typically offer 4 to 4.5 times your gross annual income. Some lend up to 5 or 5.5 times for higher earners or certain professions.
Examples:
| Household Income | Typical Maximum (4.5x) | Higher Earner Option (5x) |
|---|---|---|
| £30,000 | £135,000 | £150,000 |
| £50,000 | £225,000 | £250,000 |
| £75,000 | £337,500 | £375,000 |
| £100,000 | £450,000 | £500,000 |
Stress testing also applies — lenders check you could afford repayments if interest rates rose significantly. Affordability can also be reduced by existing commitments (car loans, credit card minimum payments, student loans).
How Long Does a Mortgage in Principle Last?
| Typical Duration |
|---|
| 30–90 days |
| 60 days most common |
If yours expires, you can apply for a new one. As long as your circumstances have not changed materially, lenders usually issue renewals quickly.
What a Mortgage in Principle Does NOT Guarantee
This is critical to understand:
- ❌ It is not a binding mortgage offer
- ❌ The lender can decline your full application even after issuing an MIP
- ❌ The quoted amount may reduce after full affordability assessment
- ❌ The interest rate on the MIP may not reflect the rate you receive on the full offer
- ❌ A specific property can be declined if the valuation comes back lower than the purchase price or reveals problems
The MIP gives you a reasonable indication, but circumstances can change and lenders reserve the right to decline at full application.
After the Mortgage in Principle: The Full Application
Once you have an accepted offer on a property, the lender begins the full mortgage application process:
- Full application form — detailed income and expenditure
- Hard credit check — once for the full application
- Property valuation — lender instructs a surveyor
- Underwriting — lender’s team reviews everything
- Formal mortgage offer — binding (subject to solicitor searches)
From MIP to formal offer typically takes 2–6 weeks, depending on lender speed and complexity.
Tips for Getting Your Mortgage in Principle Approved
- Check your credit report first with all three main agencies (Experian, Equifax, TransUnion) — fix any errors before applying
- Register on the electoral roll at your current address
- Close unused credit accounts you no longer need (high available credit can concern lenders)
- Avoid payday loans — these flag heavily on credit files
- Know your numbers: annual salary, monthly commitments, deposit amount, source of deposit
- Be consistent: the information on your MIP must match what you put on the full application
MIPs for First-Time Buyers vs Home Movers vs Remortgagors
| Buyer Type | MIP Relevant? | Notes |
|---|---|---|
| First-time buyer | ✅ Yes — important | Estate agents expect it |
| Home mover | ✅ Yes | May need for offer submission |
| Remortgager | Less critical | No property transaction, no need to show agent |
| Buy-to-let purchaser | ✅ Yes | BTL criteria different — specialist lender may apply |