Finance Calc App

UK Home affordability calculator

Work out the maximum home price you can comfortably afford using the 28/36 DTI rule.

By Mitch Duncan Last reviewed Methodology

Your finances

Loan & costs

Max home price
£366,928.99
Max loan
£306,928.99
Est. monthly payment
£2,240.00
Limit set by
front-end DTI (28%)

The 28/36 DTI rule — what lenders check

Housing costs ≤ 28% of gross monthly income (£2,240.00/mo). All debt payments ≤ 36% (£2,880.00/mo). Lenders vary — some allow up to 43% back-end for qualified mortgages.

Next step
Mortgage calculatorMonthly payment & amortizationRead the guideHow Much House Can I Afford? The 28/36 Rule Explained

Understanding your inputs

Gross monthly income
Your total monthly income before tax — the basis for the 28/36 affordability rule.
Existing monthly debt payments
Current commitments (cards, loans, car) that lenders count against your borrowing room.
Down payment
Cash you can put down; a larger deposit raises the home price you can support.
Interest rate (APR)
The mortgage rate used to convert your affordable payment into a loan amount.
Term (years)
The repayment length used to size the loan from the affordable monthly payment.
Estimated monthly property tax
Tax that competes with principal & interest inside your affordable housing budget.
Estimated monthly insurance
Insurance that, like tax, eats into the payment you can devote to the loan.

Understanding your results

Max home price
The highest purchase price your income, debts, and deposit can comfortably support.
Max loan
The borrowing portion of that price after your down payment.
Est. monthly payment
What the maximum purchase would actually cost you each month.
Limit set by
Whether your front-end (housing) or back-end (total debt) ratio is the binding constraint.
Want the full picture? How Much House Can I Afford? The 28/36 Rule Explained →

How mortgage affordability works (UK)

UK lenders don't use the US 28/36 rule. The starting point is a loan-to-income (LTI) cap — typically around 4.5× your annual income (4.49× for most of a lender's book under FCA/PRA rules) — combined with an affordability stress test.

Worked example

£60,000 income, sole applicant:

Stress testing and deposit

Affordability is assessed against committed outgoings, childcare, and credit. Typical deposits are 5–10% for first-time buyers; a 5% deposit may use the mortgage guarantee scheme. A larger deposit unlocks lower loan-to-value (LTV) bands and materially cheaper rates (e.g. 60% LTV beats 90% LTV by a wide margin).

Schemes and tax

First-time buyers can save in a Lifetime ISA (25% government bonus on up to £4,000/year toward a first home up to £450,000). Watch Stamp Duty Land Tax — a major upfront cost that varies by price and first-time-buyer status (different in Scotland's LBTT and Wales' LTT).

Common mistakes

What this doesn't cover

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Key terms

Debt-to-Income Ratio (DTI)Mortgage Pre-ApprovalDown Payment Full glossary →

Frequently asked questions

How much house can I afford on a $100,000 salary?
Using the 28/36 rule and a 6.5% rate, $100,000 of gross income supports roughly $2,330/month in housing payments (PITI). With a 20% down payment and modest existing debts, that's about $300,000–$340,000 in home price. Your exact number depends on credit, down payment size, existing debts, and current rates — enter them above for a personalised result.
What is the 28/36 rule?
The 28/36 rule is the standard underwriting guideline most lenders apply. Your total housing payment — principal, interest, property tax, insurance, plus HOA — should be no more than 28% of your gross monthly income (the front-end ratio). All debts combined, including the mortgage, should be no more than 36% (the back-end ratio).
Does down payment affect how much house I can afford?
Yes, in two ways. A larger down payment reduces the loan amount, so the monthly payment is lower — letting you qualify for a higher purchase price within the same DTI limits. It also removes private mortgage insurance once you cross 20% down, which lowers your monthly PITI by another roughly 0.5–1% of the loan amount per year.
How does student loan debt affect mortgage affordability?
Monthly student loan payments count against the 36% back-end DTI ratio, lowering the housing payment you can afford. Every $100/month of student loans removes roughly $20,000 of mortgage capacity at typical rates. Income-driven repayment plans usually count the actual minimum payment; deferred loans may still count an estimated payment depending on the lender.
Why does this calculator not factor in credit score?
Credit score affects the rate you'll be offered, not the affordability formula itself. Plug in the rate quoted to someone with your credit profile — typically tier-A rates need a 760+ FICO; sub-700 scores usually pay 0.25–0.75 percentage points more. Use that adjusted rate above to see your real affordability.

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