How do lenders calculate maximum mortgage?

Most UK lenders use an income multiple of 4–4.5× gross annual income. They also stress-test affordability at a rate typically 3% above the product rate (often around 7–8% in 2025/26) to confirm you can afford payments if rates rise.

What is an LTV ratio?

Loan-to-Value (LTV) is the mortgage amount divided by the property value. A £225,000 mortgage on a £250,000 property is 90% LTV. Lower LTV generally means access to better rates and lower mortgage insurance costs.

11 / AFFORDABILITY

Mortgage Affordability Calculator

Find out what you can actually borrow — based on income multiples, monthly commitments, and a stress test at +3%. Includes LTV breakdown.

GuideHow affordability is assessed

Mortgage Planning Cluster

Use this hub to move from the core repayment formula into affordability, offset, overpayment, and rent-versus-buy comparisons without leaving the mortgage cluster.

Your Income

Your Annual Gross Income

Partner's Annual Income (optional)Leave at 0 if solo

Monthly Debt CommitmentsLoans, credit cards, car finance

Mortgage Details

Deposit / Down Payment

Interest Rate

Mortgage Term

years

Income Multiple (lender)Typical: 4–4.5x, max 5.5x

What You Can Borrow

Maximum Property Price

£287,500

Maximum Mortgage

£247,500

4.5x annual income

Monthly Payment

£1,376

Stress Test (+3%)

£1,829

can you afford if rates rise?

Loan to Value

Deposit 13.9% — £40,000

LTV 86.1%

Affordability Check

Monthly payment vs income

✓ 30% of monthly income

Stress test vs income

✓ 40% of monthly income

Deposit vs purchase price

✓ 13.9% deposit

Cluster Hubs

Use these organising pages when you want the main calculators and supporting guides for this topic grouped in one place.

Browse the mortgage calculators hubUse the main mortgage hub to compare affordability with repayment, rent-versus-buy, and deposit-planning pages.Open the overpayment and offset hubCompare spare-cash strategies once the base mortgage payment is clear.

Related Calculators

Move sideways to closely related calculators without leaving the same topic cluster.

Use the Mortgage RepaymentMonthly payment, total interest, and full cost over any term.Use the Offset MortgageHow savings reduce mortgage interest and shorten your term.Use the Mortgage OverpaymentInterest saved and years removed by paying extra each month.Use the Rent vs BuyLong-term financial outcome of renting against buying.

Related Guides

Use these supporting explainers when you need the formula, assumptions, or decision framing behind the numbers.

How Mortgage Repayment Calculations WorkUnderstand the amortisation formula behind monthly mortgage payments.How Mortgage Affordability Is AssessedSee how income multiples, outgoings, and stress tests shape borrowing power.How Offset Mortgages Actually WorkCompare offset savings against standard mortgage interest charges.Mortgage Overpayment: How Much Does It Save?Measure how extra payments reduce lifetime interest and term length.