Mortgage Underwriting: Understanding The Process

What Happens When a Mortgage Goes to Underwriting? Find out what happens and how to avoid any potential problems.

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Home Mortgage Application Mortgage Underwriting: Understanding The Process
Pete Mugleston

Author: Pete Mugleston

Mortgage Advisor, MD

Updated: December 4, 2023

To help you approach your mortgage application with confidence, we’ll explain exactly what the underwriting process involves, the potential problems that could arise, and how to avoid or overcome them.

What is mortgage underwriting?

Mortgage underwriting is the process by which a lender decides to approve or decline your application. They will assess the level of risk involved in lending to you and whether this falls within their predetermined acceptable range.

What does mortgage underwriting involve?

In many cases, the underwriting process is completed automatically and the decision is made by an algorithm. Some more complicated cases require human judgement so they’re referred for manual underwriting. Having your case referred means that it’s too complex for a computer but that’s not necessarily bad news – a human might take a more generous view. Generally speaking, if your circumstances are in any way not simple or straightforward manual underwriting is your friend!

Each lender, from mainstream providers such as NatWest and Barclays to more specialist operators, has their own mortgage underwriting process, and no two lenders do it the same way, but usually, it includes the following components:

High-level checks

Your application will be reviewed to ensure you meet the lender’s general criteria, i.e. age, employment status, minimum income requirement, and legal residency. There’s little flexibility here so you could be automatically declined for various reasons, for example, if you’re an older borrower or if you have a low income.

Credit checks

The lender will run a credit check with one or more of the major agencies (Experian, Equifax and Transunion) and use statistical modelling to judge whether you’re likely to have issues repaying your mortgage. Every lender has a different credit check procedure and a different risk tolerance so it’s very possible that you could be declined by one lender and approved by another.

If your application is referred for manual underwriting based on your credit history, the underwriter might take into account your explanation for past issues and whether there has been an improvement in your circumstances since.

If you’re concerned at all about this stage you can download your credit reports beforehand and take steps to remove any inaccuracies or outdated information that could hinder your application. 

Also, if you do have any bad credit showing on your record – don’t panic! Speak to a specialist bad credit broker and they will help you identify the right lenders who can cater for these types of issues.  

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Affordability checks

Your lender will conduct an income multiple calculation to decide the maximum amount you can borrow. Each lender sets their own maximum income multiple, but it’s usually between four and 5.5 times your annual income.

If your affordability status is not clear-cut, a manual underwriter will look at aspects of your financial situation such as your typical monthly outgoings, your debt-to-income ratio, and any likely future changes to your finances, to judge whether you’ll be able to keep up with your mortgage repayments.

Property checks

Your lender isn’t only deciding whether to lend to you, but also whether to lend against the property you’re buying. Certain types of property are considered higher risk than others – as they may be harder to sell or maintain their value in the future (particularly relevant in the event of a repossession) – such as flats above shops and homes with non-standard construction, so each lender has a policy on which types they’ll consider.

The policy can be extremely detailed (for example, a lender might allow a flat above a retail outlet but not a flat above a commercial food outlet, or may allow a flat above a commercial food outlet in certain postcodes), so a manual underwriter may be involved and they might ask you for more details.

Fraud and money laundering checks

Before approving your application, your lender must be confident that the details you have provided are all correct and that the money you’re using for your deposit has come from a legitimate source. If they have any doubts, they may ask you to provide evidence.

How long does underwriting take?

Automatic underwriting can happen very quickly. The manual underwriting process is longer, taking anything from a few hours to a few days. This depends on how complex your case is, how experienced the underwriter is, and how busy the underwriting department is (certain times of year see a far higher volume of applications).

In a minority of cases, the underwriters might make multiple requests for more information or documentation, and this can cause slight delays. You can speed up the process by working with a broker, who’ll help you prepare your application and spot any potential issues.

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What to do if you think you’ll be declined

There are various reasons why your application could be declined during underwriting.

Most commonly, it will be due to:

  • Affordability, i.e. you don’t earn enough to qualify for the size of the loan you applied for with this lender, or your income comes from a source that they won’t consider (e.g. benefit income)
  • Deposit requirements, i.e. you don’t have a large enough deposit to borrow from your chosen lender or from a source they won’t consider (e.g. profits from cryptocurrency)
  • Bad credit, i.e. you were disqualified from consideration based on the overall picture of your previous borrowing or a specific incident in your credit history (e.g. a previous mortgage default)
  • Bank account conduct, Underwriters will want to see evidence that you’re budgeting properly for mortgage payments and all other costs associated with owning a property, such as council tax and utility bills.

So, you might have a strong suspicion that your application will be declined if you’re applying to borrow an amount that’s five times your salary or more, or if you have a low deposit or bad credit.

Don’t let this discourage you from applying for a mortgage. We’ve helped countless people to get a mortgage in these circumstances, by connecting them with a broker who specialises in similar cases.

We work with specialists in:

They can use their knowledge of these niche markets to direct you toward the lenders most likely to approve your application. They may also be able to use their personal relationships with these lenders to help push your application over the line. If you’d like to speak to one of the brokers we work with, get in touch.

What happens after underwriting

If your application is approved, you can continue with the homebuying process. Your solicitor will work with the seller’s solicitor to finalise the contracts and set a completion date. It’s a good time to look into home insurance and life insurance.

If your application is declined, the next step is to work with your broker to either renegotiate with the lender or consider a new application. Find out more by reading our dedicated article on declined mortgages.

Get matched with a broker to guide you through the underwriting process

The difference between an application that sails through the underwriting process and one that hits hurdles is often whether or not you have the right specialist on your side. So, when you choose a broker, it’s important to find someone whose experience fits your needs.

We work with numerous brokers with different specialities, and we have a proprietary broker-matching service that connects you with the right person. To get matched today, call us on 0808 189 2301 or fill in our online enquiry form.

Maximise your chance of approval with a dedicated specialist broker

Get Started Phone Icon 0808 189 2301


All mortgages go through an underwriting process but not all are referred to underwriters. Many applicants can be accepted or declined automatically based on how well they fit the lending criteria. If your case is borderline or the lender’s criteria have some flexibility, it will be referred for manual underwriting so an expert can make the decision.

It simply means that they need more information. A lender’s criteria can be very specific in certain areas so you may need to supply a lot of details to help the underwriter understand if your application falls within its policy.

Each mortgage lender employs their own team of mortgage underwriters, all of whom will carry out their due diligence based on that specific lender’s own eligibility criteria.

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About the author

Pete, an expert in all things mortgages, cut his teeth right in the middle of the credit crunch. With plenty of people needing help and few mortgage providers lending, Pete found great success in going the extra mile to find mortgages for people whom many others considered lost causes. The experience he gained, coupled with his love of helping people reach their goals, led him to establish Online Mortgage Advisor, with one clear vision – to help as many customers as possible get the right advice, regardless of need or background.

Pete’s presence in the industry as the ‘go-to’ for specialist finance continues to grow, and he is regularly cited in and writes for both local and national press, as well as trade publications, with a regular column in Mortgage Introducer and being the exclusive mortgage expert for LOVEMoney. Pete also writes for Online Mortgage Advisor of course!

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Pete Mugleston

Mortgage Advisor, MD

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