Agreement in Principle UK: What an AIP Is and How to Get One
Quick answer
An Agreement in Principle (AIP), also called a Decision in Principle or Mortgage in Principle, is a lender's provisional indication of how much it would lend you, based on a soft credit check. It is not a guaranteed mortgage offer, usually lasts 30 to 90 days, and is often free to get online in minutes.
Agreement in Principle: the key facts
| Question | Answer |
|---|---|
| Other names | Decision in Principle (DIP) or Mortgage in Principle (MIP) - the same thing |
| What it is | A lender's provisional estimate of how much it is willing to lend you |
| Credit check | Usually a soft check that leaves no mark on your file; some lenders use a hard check |
| How long it lasts | Typically 30 to 90 days, after which it can usually be renewed |
| Is it a guarantee? | No - your full mortgage application can still be declined |
| Cost | Usually free, whether you get it from a lender or a broker |
| How long it takes | Often around 10 to 15 minutes online |
Step by step
- 1
Check your credit file first
Before applying for an AIP, check your credit report and correct any errors. The lender bases its decision on what it sees there, so a clean, accurate file gives you the best result.
- 2
Gather your numbers
Have your income, deposit amount and rough monthly outgoings to hand. That is almost everything an AIP asks for; you do not usually need documents at this stage.
- 3
Choose a lender or a broker
You can apply directly with one lender, or use a whole-of-market broker that checks many lenders at once. Fee-free online brokers such as Habito run an AIP across 90-plus lenders for free in a few minutes.
- 4
Complete the soft-search application
Answer the questions online or by phone. Most providers run a soft credit check, which leaves no mark on your file, though you should confirm this before applying.
- 5
Use it to make offers
Estate agents often want to see your AIP before they take an offer seriously, so keep the certificate or reference number to hand while you house-hunt.
- 6
Convert it to a full application
Once your offer is accepted, apply for the full mortgage. The AIP is not binding: the lender now runs a hard credit check, verifies your income and values the property before making a formal offer.
An Agreement in Principle (AIP) is the first concrete step in buying a home: a lender's provisional yes, telling you roughly how much it would lend before you formally apply. It is also called a Decision in Principle (DIP) or a Mortgage in Principle (MIP), which are the same document under different brand names. The table above covers what it is, what it does to your credit file, and how long it lasts; the steps show how to get one.
An AIP matters most when you are house-hunting, because estate agents often want to see one before they take your offer seriously. If you are earlier in the journey, the first-time buyer guide explains why your income, not your deposit, sets your real budget, and first-time buyer schemes covers the help available. If you are still deciding whether to buy at all, start with the rent vs buy equation. Once you own, remortgaging and fixed vs variable cover the rate decisions that follow.
Frequently asked questions
Does an agreement in principle affect your credit score?
Usually not. Most lenders use a soft credit check for an AIP, which only you can see and which leaves no mark on your credit file. However, some lenders run a hard check, which is visible to others and can affect your score if done repeatedly. Check which type a lender uses before applying.
How long does an agreement in principle last?
Typically 30 to 90 days, depending on the lender. If it expires before you have found a property or had an offer accepted, you can usually renew it by confirming your details are unchanged. There is normally no limit on how many times you can get one.
Is an agreement in principle a guarantee of a mortgage?
No. An AIP is only a provisional indication based on the limited information you give and a soft credit check. The lender can still decline your full application after a hard credit check, income verification, and a valuation of the actual property. Never treat an AIP as a confirmed mortgage offer.
How long does it take to get an agreement in principle?
Often around 10 to 15 minutes. Many lenders and online brokers let you complete an AIP on their website by answering a few questions about your income, deposit and outgoings, and some return a decision almost instantly. You do not usually need to provide documents at this stage.
Do I need an agreement in principle to view a house?
Not to view, but estate agents often ask to see one before they take your offer seriously, and some request it before booking viewings. Having an AIP ready shows you are a credible buyer who can realistically afford the property, which can matter in a competitive sale.
Sources
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General information, not financial advice. Tax rules and figures can change; check the current position on gov.uk before acting.