How much a lender will advance is determined by tests set partly by the lender and partly by regulation.
Income multiples
A cap on lending relative to income.
Which regulators in several jurisdictions limit through rules on the proportion of lending above defined multiples.
These are macroprudential tools intended to limit systemic risk rather than to assess individuals.
Affordability assessment
Detailed examination of income and committed expenditure.
Which produces a surplus figure against which the mortgage payment is assessed.
Lenders use expenditure benchmarks alongside declared spending.
Stress testing
Assessing whether payments remain affordable at a higher interest rate.
Which is a regulatory requirement in many jurisdictions.
The stress rate materially affects borrowing capacity and has been adjusted by regulators over time.
Deposit and loan to value
The proportion borrowed against the property value.
Which determines both availability and pricing.
Rates step down at defined thresholds, so a marginally larger deposit can produce a disproportionate saving.
Credit history
Payment record, existing commitments and applications.
Which is obtained from credit reference agencies.
Checking your own file before applying is free and identifies errors that would otherwise cause a decline.
Employment type
Self-employment, contract work and variable income are assessed differently.
Which generally requires more documentation and longer trading history.
Lender criteria vary substantially here, which is where brokers add value.
Term length
Longer terms reduce monthly payments and increase total interest.
Which has led to growth in very long terms, extending borrowing into later life.
Regulators have noted this trend and its implications.
Before applying
Check your credit file, gather documentation, and get a decision in principle to establish the realistic range.
This is general description rather than financial advice.
Interest-only and repayment
Repayment mortgages clear the balance over the term; interest-only leaves it outstanding.
Which requires a credible repayment strategy that lenders assess.
Interest-only lending was restricted substantially after previous problems with maturing loans.
Fixed and variable rates
Fixed periods provide certainty and end, moving borrowers to a higher standard rate.
Which is why remortgaging before the end of a fixed period matters.
Product transfer with the existing lender is generally simpler than switching.
Early repayment charges
Fees for leaving a fixed deal before it ends.
Which are set out clearly and are frequently substantial.
Timing a remortgage against these charges is a straightforward calculation.
Overpayments
Most products permit overpaying up to a limit each year without charge.
Which reduces total interest substantially over a term.
The effect of modest regular overpayments over decades is larger than most borrowers expect.
Getting advice
Regulated advisers assess suitability and carry responsibility for the recommendation.
Joint applications
Combined incomes and combined commitments.
Which increases borrowing capacity and creates joint liability.
Both parties remain liable regardless of any private arrangement between them.
Guarantors and family assistance
Arrangements where a family member supports an application.
Which carries real risk for the supporting party.
Independent legal advice is generally required and is worth taking seriously.
Additional costs
Legal fees, surveys, transaction taxes, insurance and moving costs.
Which are substantial and are frequently underestimated.
Budgeting for them separately from the deposit avoids a common shortfall.
Surveys
A lender valuation is not a survey of condition.
Which is a distinction that catches buyers out.
A fuller structural survey costs more and identifies problems that affect value and safety.
If circumstances change
Lenders have forbearance obligations and options including term extension and payment concessions.
Contacting them early produces better options than missing payments does.
Why capacity varies between lenders
Affordability models, income treatment and stress rates differ.
Which means two lenders can offer materially different amounts to the same applicant.
This is why comparison, or a broker with access to multiple lenders, produces better outcomes than approaching one bank.
A note
This describes how assessment generally works and is not financial advice; regulated advice is the appropriate route for a decision.
A final observation
The stress test, the income multiple and the affordability assessment were all introduced or tightened after periods when lending was too loose.
They constrain borrowers who would repay comfortably and exist because the alternative produced worse outcomes at scale.
First-time buyer schemes
Government-supported schemes exist in many countries with defined eligibility.
Which change periodically and are published by the relevant departments.
Some carry conditions on resale or on shared equity that are worth understanding fully.
Shared ownership
Buying a share and paying rent on the remainder.
Which reduces the deposit needed and carries specific costs and restrictions.
Service charges and staircasing terms are the aspects most frequently underestimated.
One more thing worth knowing
Credit reference agencies must provide access to your file, generally free.
Which frequently reveals errors, closed accounts still showing as open, and addresses linked incorrectly.
Correcting them before applying costs nothing and removes a common cause of decline.
The summary
Income multiples, detailed affordability assessment, stress testing and credit history, applied differently by each lender.