Mortgage calculators show £80,000 gap for same buyer as brokers warn they are just a "rough guide"

Mortgage calculators show an £80,000 gap between how much they say a buyer can borrow as brokers warn they are just a “rough guide” for borrowers.

New Newspage research, sponsored by onlinemortgageadvisor.co.uk, found the same buyer could be told they can borrow anything from £160,000 to £240,000.

Newspage tested seven mortgage calculators on 6 October using a single 30-year-old first-time buyer earning £40,000, with a £10,000 deposit (5%) on a £200,000 home, needing to borrow £190,000.

Some calculators said the home was affordable for the applicant, while others said it was not.

The same first-time buyer is told anything from £160,000 to £240,000. Barclays says the buyer can borrow £160,000, while Nationwide’s Helping Hand gives £240,000: an £80,000 gap. 

MoneyHelper gives up to £200,000 while TSB, Lloyds, Halifax and HSBC all give £179,600.

Brokers said the £80,000 gap does not mean any of the calculators are necessarily wrong, but reflects the different affordability models, income multiples and risk appetites used by individual lenders.

They warned that calculators provide only a “rough guide” and may not account properly for factors such as bonuses, overtime, self-employed earnings, second-job income, existing debts or past credit problems.

Pete Mugleston, Mortgage Advisor & Managing Director at Derby-based onlinemortgageadvisor.co.uk, urged caution over using mortgage calculators.

He added: "No standalone calculator can offer 100% certainty. The reality is that 100+ lenders vary wildly across generosity, acceptable income types, age, credit history, and property criteria. 

"Navigating this is tough even for advisers – we regularly help clients who were previously quoted a fraction of what they could actually borrow – so for consumers going solo, it's a minefield. While multiplying income by 4x up to 7x gives a rough starting point, standard calculators quickly fall over for anyone with variable income, credit blips, or existing debts. 

"Crucially, definitive decisions sit behind an application wall with each lender, and applying to dozens of lenders isn't realistic. Add the fact that roughly a third of deals are broker-exclusive, and a DIY comparison will always miss key options. Basically, to get it right, you need a very good broker with access to smart technology."

Rough guide

Craig Fish, Director at London-based Lodestone Mortgages, said lenders are not “wrong” – they just have different criteria.

He added: "An £80,000 gap for the same buyer on the same salary tells you all you need to know about online calculators. Every lender runs its own affordability model, with its own view on income multiples, outgoings and stress testing. Nationwide's Helping Hand is built to stretch for first-time buyers, reaching six times income here, while Barclays stops at four. 

"Neither is wrong, they are simply different lenders with different appetites for risk. Calculators are a rough guide and nothing more. They can't see the detail, and the detail is where lending decisions are made, particularly how bonus, overtime, self-employed or second-job income is treated, which varies widely between lenders. A calculator gives you a number, a broker gives you a lender. 

"Speak to a whole-of-market broker before you start viewing. Some brokers work with a handful of lenders, others with 90 plus. Give yourself the maximum choice, because the right lender can be the difference between buying now and waiting years."

Matt Coulson, Founder at Rickmansworth-based Heron Financial, said lenders assess borrowers differently.

He added: "That £80,000 gap looks alarming, but it's not a malfunction. Each calculator is giving you that lender's honest answer, and lenders genuinely assess the same person very differently. The spread usually comes down to income multiples and the specific product. 

"Nationwide's Helping Hand is built to stretch borrowing for first-time buyers, so it lands near six times income, while a more cautious lender sits closer to four. Same salary, same deposit, very different appetite. So calculators are useful for a rough sense of the range, but the one real mistake is treating any single number as what you can borrow, because your figure depends entirely on which lender you approach. 

“That's the useful part of this story: the gap is a map of which lenders will back someone in your position and which won't, and reading that map is the whole job. A calculator can show you the spread. Working out which end of it you actually sit at, and with whom, is what a broker is for.”

Starting point

Tracey Dixon, Buy-to-Let Mortgage Specialist & Owner at Cardiff-based Pure Mortgage and Protection, said calculators are “useful starting points”.

She added: "A mortgage calculator can give you a number. It cannot give you the whole lending decision. I have seen this with my own clients: the same circumstances can produce very different borrowing figures across lenders. That can mean the difference between buying a home and believing it is out of reach. 

"Lenders assess income, commitments and expenditure differently, and enhanced borrowing schemes have their own eligibility conditions. These calculators are therefore not necessarily comparing like for like. They are useful starting points, but a low result can unnecessarily discourage someone, while a high result can create expectations that do not survive a full assessment. 

“My advice is to speak to a broker before setting your property budget. We can review the full circumstances, check suitable lenders and obtain a decision in principle. Even that remains subject to underwriting and property checks. The highest figure on a screen is only useful if the borrower qualifies for it.”

Michelle Lawson, Director at Fareham-based Lawson Financial, said borrowers should speak to a broker for advice.

She added: "This demonstrates the need for advice as some borrowers will run some numbers and think that their position isn’t proceedable. There are many lenders who all have different lending policy and differing ways they take the various income streams into account. 

"The borrowing capacity can range significantly but brokers have the experience, knowledge and additional system access to drill this down accurately. Even some of these that we use in the industry are for guidance only. Brokers can often make what seems impossible possible."

ENDS