Going to your bank gets you one number. A whole of market broker often unlocks £20,000 to £50,000 more borrowing on the same salary. This calculator shows you all three scenarios honestly, plus the lender stress test most calculators leave out.
UK mortgage lenders do not lend you whatever you ask for. They use a calculation called an income multiple, which is a maximum loan expressed as a multiple of your gross annual income. The standard UK figure is 4.5 times your salary. So someone earning £40,000 can typically borrow up to £180,000. Joint applicants combine both incomes, usually getting a slightly lower household multiple of around 4 to 4.5 times the total.
Above 4.5x, things get harder. The Financial Conduct Authority caps the proportion of mortgages each lender can issue above this multiple. Lenders have to ration these spaces, so accessing them requires going through a broker who knows which lender currently has capacity. Higher earners (typically £75,000 plus), professionals like doctors, lawyers, accountants, teachers, and people in some skilled trades often qualify for stretched multiples up to 5.5x or even 6x through specialist routes.
This catches almost everyone. When you walk into your own bank for a mortgage quote, you see only their products. They will quote you their standard income multiple (often the most conservative on the market) and offer you their own interest rates. You leave thinking "this is what mortgages cost". You are wrong.
A whole of market broker compares 90+ UK lenders on your behalf, including building societies, challenger banks, and specialist providers most people have never heard of. The same applicant who gets £175,000 quoted at their high street bank might be offered £225,000 from a specialist lender at a slightly better rate. The maths can mean tens of thousands of pounds more borrowing power on the same salary.
Most brokers are free to use because they are paid by the lender, not by you. They also handle the paperwork, chase the application, and know which lenders to approach for non standard situations like self employment, recent job changes, or contract work. The 10 hours of admin they save is worth real money in itself.
Even after a lender calculates your maximum offer, they apply a stress test. This is an affordability check that simulates what your monthly payments would look like if interest rates rose by around 3 percent above current levels. If today's average rate is 4.8 percent, your stress test runs the maths at 7.8 percent. If you cannot afford the higher payment from your monthly take home, the lender reduces your offer or rejects the application entirely.
This is why some applicants are offered less than 4.5x their salary in practice, particularly those with high outgoings, lots of dependents, or significant existing debt. The stress test was tightened after the 2008 financial crisis and is one of the main reasons UK mortgage defaults are now historically low. It also means your "comfortable affordability" and the "maximum offer" are usually different numbers. Just because a lender will lend you the maximum does not mean you should borrow it. Run the stress test number through your own monthly budget honestly before agreeing.
Salary is the headline number, but lenders examine several other factors that can dramatically change your offer. Existing debt commitments are deducted at roughly £25 to £30 of borrowing power per £1 of monthly debt. So a £200/month car finance commitment reduces your maximum mortgage by around £6,000. Clearing one or two debts before applying often unlocks £15,000 to £30,000 more borrowing.
Dependents reduce borrowing by approximately £5,000 to £8,000 each, reflecting the assumed cost of children. Bonuses and overtime are typically counted at 50 percent unless they are guaranteed and contractual, and lenders usually want at least two years of bonus history. Credit score and history matter both for the offer amount and the interest rate. Missed payments, late payments, and high credit utilisation in the 12 months before applying can cost you £20,000 to £40,000 of borrowing power.
For self employed applicants, lenders look at two to three years of accounts or SA302 tax calculations. They typically use the average of those years rather than the most recent, which often disadvantages people whose business is growing. Specialist self employed lenders use just the most recent year, which is one of the main reasons brokers are essential for non employed applicants.
The LTV ratio is the size of your loan as a percentage of the property price. A £180,000 mortgage on a £200,000 property is 90 percent LTV. Lenders charge significantly different interest rates at different LTV bands. The cheapest rates are typically reserved for 60 percent LTV (40 percent deposit), with rates increasing in steps at 75, 85, 90, and 95 percent LTV.
The practical impact is dramatic. On a £200,000 mortgage, the difference between a 90 percent LTV rate (around 5.0 percent) and an 85 percent LTV rate (around 4.7 percent) is roughly £35 per month or £420 per year. Over a 25 year term, that is £10,500 saved by putting down an extra 5 percent deposit. This is why many buyers wait an extra 6 to 12 months to save more deposit, because the long term saving easily justifies the wait.
For first time buyers, a Lifetime ISA can boost the deposit by 25 percent through the government bonus, potentially moving you from 90 percent to 85 percent LTV without saving any extra yourself. This is one of the biggest benefits of LISAs that most calculators ignore.
Beyond the deposit, several costs catch first time buyers off guard. Stamp duty is currently zero for first time buyers on properties up to £425,000, then 5 percent on the portion above that up to £625,000. Standard rate buyers pay 5 percent above £250,000. On a £350,000 property, a first time buyer pays nothing in stamp duty, while a second time buyer pays £5,000.
Legal fees for conveyancing typically run £1,500 to £2,500 depending on complexity. Survey costs range from £400 (basic) to £1,000 plus (full structural survey on older properties). Mortgage arrangement fees can be £999 to £1,999, though some lenders offer fee free options at slightly higher rates. Moving costs for removals run £400 to £1,500 depending on distance and how much stuff you have.
Add these together and the typical first time buyer needs around £3,000 to £6,000 above the deposit ready before completion. Builders' incentives, deposit boost schemes, and some mortgage products can offset some of these, but plan for them in your savings target rather than being surprised the week before completion.
Three concrete steps. One: get a free Decision in Principle (DIP) from a whole of market broker. This soft search shows your actual maximum borrowing across multiple lenders without affecting your credit score. It takes about 15 minutes. Estate agents take buyers with a DIP far more seriously than those without, which can be the difference between getting an offer accepted in competitive areas.
Two: stop applying for new credit immediately. Each new credit application leaves a hard search on your credit file, which lenders see and dislike. Even small things like a phone contract upgrade or buy now pay later applications can reduce your borrowing power for 6 to 12 months. If you are within a year of applying for a mortgage, hold off on anything that requires a credit check.
Three: clear or reduce existing debts strategically. Each £100 of monthly debt commitment reduces your borrowing by roughly £3,000. Clearing a £150/month car finance balance unlocks around £4,500 more mortgage. The economics often justify aggressive debt clearance in the months leading up to a mortgage application, even if you have to delay the application by a few months to do it.
UK lenders typically lend between 4 and 4.5 times your annual income, though some specialist lenders offer up to 5.5x for higher earners or specific professions. On a £40,000 salary, this means you could borrow between £160,000 (high street) and £220,000 (specialist), with most lenders sitting at around £180,000 (4.5x). Joint applicants combine both incomes, usually getting a slightly lower combined multiple of around 4x to 4.5x the household total.
Mortgage lenders use an income multiple to set the maximum loan they will offer. The standard UK figure is 4.5x annual gross income, meaning a £50,000 earner could get up to £225,000. Above this, only specialist lenders will lend, because regulators cap how many over 4.5x mortgages each lender can issue. Higher earners over £75,000 and professionals like doctors, lawyers, and teachers often qualify for stretched multiples through brokers.
Mortgage brokers compare offers from 90+ lenders, including specialist ones not available directly to consumers. They typically secure 0.5x to 1x higher income multiples than going to your own bank, meaning £20,000 to £50,000 more borrowing on a £40,000 salary. Most reputable brokers are free to use because they are paid by the lender, not you. They also handle paperwork and chase the application, saving 10+ hours of admin.
Even after offering you a maximum loan amount, UK lenders apply a stress test, checking you could still afford repayments if interest rates rose by around 3 percent above current rates. If today's rate is 4.8 percent, the stress test calculates affordability at 7.8 percent. If you cannot pass this test, the lender reduces your offer or rejects the application. This is why your calculator estimate may be lower than 4.5x your salary in practice.
The minimum deposit is 5 percent of the property price, but 10 percent gets you significantly better interest rates and 15 to 20 percent unlocks the cheapest deals. On a £250,000 property, a 5 percent deposit is £12,500, while a 10 percent deposit is £25,000. Most first time buyers in the UK now put down 15 to 20 percent, partly because higher LTV (loan to value) mortgages have higher rates. Use a Lifetime ISA for the 25 percent government bonus on deposit savings if you qualify.
Yes, significantly. Your credit score affects both whether you are approved and the interest rate you are offered. A poor credit score can mean rejection from high street lenders or rates 1 to 2 percent higher than the best rates, which on a £200,000 mortgage is £100 to £200 extra per month. Missed payments, defaults, CCJs, and high credit utilisation in the 12 months before applying are particularly damaging. Check your credit file with all three UK agencies (Experian, Equifax, TransUnion) before applying so you can fix any errors.