What is a mortgage in principle (MIP)?

A mortgage in principle is a document, usually from a lender or broker, that tells you roughly how much you may be able to borrow with a mortgage.

It's sometimes called:

  • Agreement in Principle (AIP)

  • Decision in Principle (DIP)

  • Approval in Principle

How will it help?

The main reason to get a MIP is to understand better how much you can borrow based on your income and outgoings. You can then look for properties within your price range, or you might decide to continue saving up.

Having a MIP shows estate agents that you're a serious buyer, and puts you in a better position to make an offer that the seller is more likely to accept. It'll also help you stand out from prospective buyers who do not have a MIP. 

Keep in mind that having a MIP does not guarantee that you can get a mortgage. It's designed to give you a good idea of what you could borrow.

How reliable is a mortgage in principle?

A mortgage in principle is not a guarantee that you’ll be able to borrow any specific amount.

You’ll need to complete a full application and have the lender check your earnings and credit history before you get a mortgage.

It still gives you a good idea of what you could borrow and could also put you in a better position if you want to make an offer on a house.

A MIP is usually more accurate than an online mortgage calculator. But it is not a guarantee that you'll be able to get a mortgage.

How accurate is a mortgage in principle?

The accuracy of your MIP will depend on who you get it from.

When you get a MIP from Trussle, we check your credit history and eligibility with 18 lenders to give you a really accurate idea of how much you'll be able to borrow.

If you get a MIP directly from a lender's website, it will likely be quite accurate as well, though it's still not a guarantee that they will lend you that amount of money.

As our MIP takes into account many different lenders, you get a better idea of what you could borrow compared to when you get a MIP from one lender.

How to apply for a mortgage in principle

To get your MIP, tell us about your situation and we’ll check how much you could borrow from a range of mortgage lenders.

Who can get a MIP?

To get a MIP with us, all applicants must be:

  • 18 or over

  • living in the UK

  • have the right to live and work in the UK

We need to know a few things about you so we can work out how much lenders would be willing to lend to you.

When applying for a mortgage in principle, we'll ask for your:

  • address history

  • employment status

  • salary

  • credit commitments

It's okay if you do not have all your information to hand. We'll save your profile as you go, so you can come back to it at any point.

You will not have to give as much paperwork or information as a mortgage application when you apply for a MIP with us.

Other lenders may ask you for:

  • payslips

  • 3 years of accounts if you’re self-employed

  • 3 months' worth of utility bills as proof of your current address

  • photo ID, such as a passport or driving license

Once you have the MIP, you can use it to make an offer on a home.

If the seller accepts your offer, you can apply for a mortgage with your chosen lender or broker.

How long does a mortgage in principle last?

When you get a MIP from a lender, you usually have about 3 months before your MIP expires (between 30 and 90 days).

You can reapply if it takes longer than planned to find the home you want to buy or if you find new, more competitive mortgage deals on the market since you arranged the MIP.

If your lender carries out hard credit checks, try not to apply too many times as it could damage your credit score.

Does a mortgage agreement in principle include a deposit?

Your mortgage in principle amount will not include your deposit amount.

However, knowing your deposit amount will be helpful in getting a better idea of what you might be able to borrow for your mortgage.

Does a mortgage agreement in principle affect your credit score?

We will do a soft credit check when you've answered all of the questions.

This soft credit check will tell us if you have any black marks on your credit history that could impact your mortgage eligibility.

A soft credit check does not affect your credit score.

A mortgage expert from Trussle will get in touch with you afterwards and advise you on the next steps to get a mortgage, including how to improve your credit score if necessary.

Do you need a credit report to get a mortgage in principle?

You might need a credit report if you’ve got a history of bad credit.

We’ll let you know if we need to see your credit report once you’ve answered the questions.

What happens after a mortgage in principle?

If everything looks good, we’ll work out how much you could afford to borrow.

We'll email you your mortgage in principle and you can download it right away.

Once the seller accepts your offer on your new home, you can add the property’s details to your profile.

This way, we can start finding the right mortgage for you.

Why get a mortgage in principle with Trussle

We’ve made getting a mortgage in principle free and simple.

You can get a mortgage in principle online at a time that suits you.

You can then print or download it to start your property search straight away.

Getting a mortgage in principle with us is easy and will set you up nicely for when you go to make an offer on your dream home.

Here’s why:

  1. We run a soft credit check to see your eligibility with 18 lenders

  2. Our MIP accurately calculates how much you could borrow from those lenders

  3. Getting a MIP with us is free and simple to do 

  4. Once you’ve set up your profile with us you can come back to it whenever you want to update your MIP

Where to go from here

Compare mortgage deals

We'll help you find the right deal.

Compare deals

See how much you could borrow

Take a second to pop a few details into our calculator


Calculate your stamp duty

Calculate how much stamp duty you'll pay

Calculate stamp duty
Looking at pictures

Get a mortgage with Trussle today

  • Our remortgage customers save an average of £171 a month*

  • Trussle is fee-free for most customers**

  • 5-star Trustpilot rating from over 5,000 reviews

  • 12,000 mortgage deals from 90 lenders

  • Skip the paperwork: apply online any time

*The savings figure is from Trussle mortgage customers in September 2022. **You may have to pay a fee depending on your circumstances and credit history. Learn more.

Your home could be repossessed if you don't keep up repayments on your mortgage.

You may have to pay an early repayment charge to your existing lender if you remortgage.

What people are saying about Trussle...