What a Low Credit Score Really Costs You on a Mortgage

A weak credit file rarely shows up as one clear bill. On a mortgage it works in layers: a rate slightly higher than the best on the shelf, a tighter limit on what you can borrow, a shorter list of deals to choose from, and a steeper price each time the deal ends and you reprice. None of these arrive on a statement, which is why the total is easy to miss.

How Lenders Turn Your Credit File Into a Rate

Mortgage lenders do not read your credit file cold. Most pull data from Experian, Equifax and TransUnion, the three main credit reference agencies, and feed it into their own scoring system alongside your income, deposit, existing debts and spending.

Two things follow from that. First, no single credit score threshold decides mortgage applications across the UK, because every lender weights the information differently and applies its own criteria. Second, the score you see on an agency’s app is not the score your lender uses. The internal score a lender works out is not one you will usually be shown, so the agency number is best read as a general indicator of how your file looks rather than a pass mark.

What the scoring is measuring is risk. A higher score generally points to lower risk, which widens the choice of products and can bring cheaper rates. A weaker score can make borrowing more difficult, or simply dearer, and that is where the costs below begin.

Layer One: A Higher Interest Rate

Borrowers with higher credit scores are generally offered lower interest rates, while those with lower scores may face higher rates. The gap can look trivial, a fraction of a percentage point you would barely notice in an advert. The effect is not, because the same small difference applies to every monthly payment for the whole deal and compounds into a substantial difference in the overall cost of the loan.

One practical point when comparing: the rate a lender offers you depends on its own criteria and on your circumstances, not only on the headline figure in the advert.

Because around 86% of UK mortgages sit on fixed rates, most borrowers pay one set rate for the length of their deal. A weak file does not just make the first month dearer. The rate you accept is the rate you live with until the deal ends, so the cost is locked in rather than spread thinly.

Layer Two: A Bigger Deposit, or a Smaller Loan

The second layer is the deposit. Loan-to-value, usually shortened to LTV, is the size of the loan as a percentage of the property’s value, so the smaller your deposit, the higher the share you need to borrow.

A weaker credit profile interacts with this in two ways. Lenders weigh the deposit alongside the file, the income and existing debts when deciding what to offer, and a smaller deposit means borrowing a larger share of the property’s value. That can restrict both the deals open to you at the level you sit at and the size of the loan you are offered compared with what the affordability figures alone would suggest. If you cannot stretch the deposit, you may be able to borrow less than you hoped, which narrows the price range you can shop in.

The lever is the same whatever your file looks like: the more deposit you bring, the lower the share you need to borrow, and the stronger your position when a lender weighs the whole application. Our guide to deposits and loan-to-value sets out how this works.

Layer Three: Fees, Arrangement Charges and Fewer Deals

The third layer is the fee side of the deal, and the shrinking market behind it. A lower score shrinks the pool of lenders and products that will consider your application. That has a cost before any fee is charged, because a shorter list means less competition working in your favour.

Fees then pile on in the usual places. An arrangement fee is a charge a lender makes for setting up a particular deal, and it varies between products; a headline rate that looks sharp can carry a large fee that changes the sums. On top sit the standard costs of buying a home, such as legal fees and surveys, and if you use a broker or adviser there may be a fee for mortgage advice, which can be up to 1% of the amount borrowed, with 0.3% a typical figure.

With fewer deals to compare, you also have fewer chances to find products with low or no arrangement fees, or to play one offer against another. Comparison work matters more, not less, when the shelf is short.

Layer Four: The Cost Each Time the Deal Ends

A fixed-rate mortgage is a snapshot, not a permanent state. When the deal period ends, the rate changes, and what you pay next depends on the deal you are able to arrange at that point. This is where a weak credit file can charge you a second time: the same layers, a higher rate, a shorter shortlist, apply to the next deal as applied to the first.

There is support worth knowing about. Under the Mortgage Charter, an agreement between the government and mortgage lenders, you can arrange a new rate with your existing lender up to six months before your deal ends, without a fresh affordability check. Lenders have also committed to contact customers ahead of fixed-rate deals ending, setting out their options and how to access support well before payments change. If keeping up payments becomes a worry, the Charter allows a temporary move to interest-only payments, where you pay only the interest and the loan itself does not shrink, for six months, and asking your lender for this support does not affect your credit score.

The Four Layers Side by Side

Layer	What it costs you	What pushes it up	What pulls it down
Interest rate	A higher rate on every monthly payment for the whole deal	A lower credit score, recent credit applications	A longer, cleaner payment history
Deposit and loan-to-value	A smaller choice of deals, or a smaller loan than you hoped for	A small deposit, a high share of borrowing	A larger deposit, a lower loan-to-value
Fees and choice	Arrangement fees and less room to compare	A shorter shortlist of lenders and deals	Time spent comparing the whole market
Deal end	The same layers repeat when you reprice	Leaving the deal to end with no new rate arranged	Booking a new rate early with your existing lender

Read down the table and the pattern is clear. Each layer is modest on its own. Together they are the difference between the deal a strong file gets and the deal a weak one settles for.

When a Lender May Decline Rather Than Charge More

Charging more is not the only outcome. A lower score cuts down how many lenders and deals will take you on, and in some cases the answer is simply no: your credit score can affect whether you can get a mortgage at all, and the higher the number, the more likely you are to be offered one. There is no single cut-off, because lenders weigh the whole picture, including income, spending, existing debts and the deposit.

Affordability is assessed separately from credit history. A lender looks at whether your monthly payments will be affordable, and considers changes that might affect that, such as interest rates rising or redundancy. Someone with a thin file but a comfortable income may do better than the score alone suggests, which is one reason a decline from one lender is not the end of the search.

What is worth avoiding is the scattergun response. Applications involve hard searches, the checks lenders make that leave a mark on your file, and several of them in a short period can affect your score. Applying widely after one decline can make the next application harder, not easier.

What You Can Realistically Improve Before You Apply

None of the steps below guarantee an outcome, and none work overnight. They are the things the scoring systems themselves respond to.

• Check your file with all three agencies before you apply, and correct anything wrong. Our guide to what to check on your credit file before a mortgage walks through the details worth reading.
• Protect your payment history, the record of whether you make credit repayments on time. It is one of the main inputs to a score.
• Look at how much debt you carry and how much of your available credit you are using.
• Space out new credit applications, since multiple hard searches in a short period can affect your score.
• If you have no credit history at all, that can also count against you, because lenders have nothing to go on when judging how you manage borrowing.

Watch out

Several hard searches in a short period can affect your credit score. If an application is declined, look at your file and work out why before applying elsewhere.

If money is already tight, acting early beats waiting. Under the Mortgage Charter you can speak to your lender about support without it affecting your credit score. And where a gap remains, a larger deposit does work a score cannot, by reducing the share you need to borrow and putting you in a stronger position.

More on this site

• Mortgage Agreement in Principle: What It Tells You and What It Doesn’t: where a soft-check decision fits in before you make offers on properties.
• Fixed, Tracker or Variable: How Mortgage Rate Types Compare: what you are choosing between when your current deal ends and you reprice.
• How Lenders Work Out How Much You Can Borrow for a Mortgage: the affordability side of the decision, which sits alongside your credit file rather than replacing it.

Your questions

Is there a minimum credit score for a mortgage in the UK?
No. Lenders use their own scoring systems and criteria, so no single number guarantees approval. A lower score can shrink the choice of lenders and deals open to you, but it does not automatically mean you cannot get a mortgage.

Do several mortgage applications in a short period affect my credit score?
Applications involve hard searches, the checks lenders make that leave a mark on your file. Several hard searches in a short period can affect your score, so it makes sense to space applications out rather than apply widely at once.

How much can a slightly higher mortgage rate cost me?
Even a small difference in the interest rate has a substantial effect on monthly payments and the overall cost of the loan, because it applies to every payment for the whole deal. The weaker your file, the further you may sit from the best rates on offer.

Can I arrange a new mortgage deal without a fresh affordability check?
Under the Mortgage Charter, you can arrange a new rate with your existing lender up to six months before your deal ends without a fresh affordability check. Moving to a different lender involves that lender’s own assessment.