Mortgage Affordability Calculator

Q: What is the FCA mortgage stress test?

The FCA requires lenders to check borrowers can still afford their mortgage if interest rates rise. The standard stress test adds around 2 percentage points to the current rate. For example, if your rate is 4.5%, the lender must verify you can afford payments at 6.5%. This protects borrowers from overextending.

Q: How much deposit do I need for a UK mortgage?

The minimum deposit is typically 5% (95% LTV). A larger deposit unlocks better rates: 10% deposit drops rates noticeably, and the biggest improvements come between 5% and 15%. Beyond 25% deposit (75% LTV), rate improvements become marginal. For a £300,000 property, moving from 5% to 10% deposit could save tens of thousands in interest.

Q: What are current UK mortgage rates in 2026?

As of March 2026, indicative UK mortgage rates are: 2-year fixed ~4.1%, 5-year fixed ~4.2%, SVR ~7.5%. Rates vary by LTV — at 95% LTV expect ~5.5%, at 75% LTV around 3.9%. Individual rates depend on lender, credit score, loan size, and product type.

Q: Does existing debt affect how much I can borrow?

Yes, significantly. Lenders assess total monthly commitments including car finance, credit cards, and personal loans. As a rough guide, every £100/month of existing debt reduces borrowing capacity by approximately £4,800. Consider paying off debts before applying to maximise your borrowing power.

Find out how much you can borrow, stress-test your payments against rate rises, and see how your deposit size affects monthly costs. UK rates and FCA rules for 2025/26.

Calculate your maximum mortgage borrowing based on income and deposit

Annual income (gross)

Your gross annual salary before tax

Partner income (gross)

Leave as 0 for sole applications

Deposit

Your total savings for deposit

Existing monthly debts

Car finance, credit cards, loans, etc.

Income multiple

Most lenders offer 4-4.5x; up to 5.5x for professionals

Mortgage term

years

Standard: 25 years. Max typically 35-40 years.

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How to Use This Calculator

How Much Can I Borrow? tab

Enter your annual income, partner income (if joint application), deposit, and existing monthly debts. Choose an income multiple (4-5.5x) to see your maximum borrowing, maximum property value, LTV ratio, and estimated monthly payments at current 2-year fix, 5-year fix, and SVR rates.

Stress Test tab

Check whether you can still afford your mortgage if rates rise. Enter your income, monthly bills, existing debts, and current rate. The calculator applies the FCA stress test (+2%) and also shows affordability at the SVR (~7.5%). You get a clear PASS or FAIL result with your disposable income at each rate.

Deposit Impact tab

Enter your target property value to see a side-by-side comparison of 5%, 10%, 15%, 20%, and 25% deposits. For each level you see the LTV, indicative rate, monthly payment, total interest, and interest saved vs a 5% deposit. The calculator highlights the best value threshold where you get the most savings per pound of extra deposit.

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The Formula

Monthly mortgage payments are calculated using the standard annuity formula:

Monthly Payment = L × [c(1 + c)^n] / [(1 + c)^n − 1]

Where:
L = Loan amount (property price − deposit)
c = Monthly interest rate (annual rate ÷ 12)
n = Total number of payments (term in years × 12)

Maximum Borrowing = (Total Income × Multiple) − (Monthly Debts × 48)
Maximum Property = Maximum Borrowing + Deposit
LTV = (Loan / Property Value) × 100

The income multiple approach is a simplified version of what lenders use. Most high-street lenders offer 4-4.5x combined income. Specialist lenders may offer up to 5.5x for professionals such as doctors, lawyers, and accountants with predictable career earnings growth.

Existing debts reduce your borrowing capacity. As a rough rule, lenders deduct approximately 4 years' worth of committed monthly payments (monthly debt × 48) from your maximum borrowing.

Example

Sarah — Marketing Manager, 32, Bristol

Sarah earns £45,000 per year. Her partner earns £35,000. They have £60,000 saved for a deposit and pay £200/month on a car loan. They want to know how much they can borrow and whether they can afford a rate rise.

How Much Can I Borrow? tab

Combined income£80,000

Income multiple4.5x

Gross borrowing£360,000

Debt adjustment (£200 × 48)−£9,600

Maximum borrowing£350,400

Deposit£60,000

Maximum property£410,400

LTV85%

Monthly payment (5yr fix at 4.2%)~£1,895

At 4.5x income, Sarah and her partner could afford a property up to £410,400 with an 85% LTV, qualifying for competitive rates around 4.3%.

Stress Test tab

At the stress rate of 6.2% (current 4.2% + 2%), their monthly payment would rise to ~£2,296. With monthly bills of £1,500 and net income of ~£4,667, they would have £671/month disposable — a comfortable PASS.

FAQ

How much can I borrow for a mortgage in the UK? ▼

Most UK lenders offer between 4 and 4.5 times your annual income for a standard mortgage. For example, on a £50,000 salary, you could typically borrow £200,000-£225,000. Joint applicants can combine incomes. Some specialist lenders offer up to 5.5x for professionals like doctors, lawyers, and accountants. Your actual borrowing limit also depends on your credit score, existing debts, monthly outgoings, and the lender's own affordability model.

What is the FCA mortgage stress test? ▼

The Financial Conduct Authority (FCA) requires lenders to check that borrowers can still afford their mortgage if interest rates rise. The standard stress test adds around 2 percentage points to the current rate (or uses a minimum stress rate, whichever is higher). For example, if your mortgage rate is 4.5%, the lender must verify you can afford payments at 6.5%. This protects borrowers from overextending and is a key part of the UK's responsible lending rules introduced after the 2008 financial crisis.

How much deposit do I need for a UK mortgage? ▼

The minimum deposit for a UK mortgage is typically 5% of the property value (95% LTV). However, a larger deposit unlocks significantly better rates. At 10% deposit (90% LTV), rates drop noticeably. The biggest rate improvements come between 5% and 15% deposit. Beyond 25% (75% LTV), rate improvements become marginal. For a £300,000 property, a 5% deposit is £15,000 but a 10% deposit (£30,000) could save you tens of thousands in interest over the mortgage term.

What are current UK mortgage rates in 2026? ▼

As of March 2026, indicative UK mortgage rates are approximately: 2-year fixed ~4.1%, 5-year fixed ~4.2%, and SVR (Standard Variable Rate) ~7.5%. Rates vary by LTV band — at 95% LTV you might pay ~5.5%, while at 75% LTV you could get ~3.9%. These are averages; individual rates depend on your lender, credit score, loan size, and product type. Always compare multiple lenders and consider using a mortgage broker.

Does existing debt affect how much I can borrow? ▼

Yes, significantly. Lenders assess your total monthly commitments including car finance, credit cards (minimum payments), personal loans, and student loans. As a rough guide, every £100/month of existing debt reduces your borrowing capacity by approximately £4,800 (£100 × 48). Before applying for a mortgage, consider paying off or reducing debts to maximise your borrowing power. Some debts with fewer than 6 months remaining may be excluded by lenders.

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