First-Time Buyer Affordability Calculator

Find out how much you can afford as a first-time buyer. Enter your income, deposit and lending criteria to see your maximum property price, monthly repayment, stamp duty and total upfront costs.

Last updated: April 2026

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How mortgage affordability is assessed in the UK

UK mortgage lenders use two main methods to determine how much you can borrow: income multiples (typically 4–4.5 times your gross annual income) and affordability modelling (stress-testing the repayment against a higher interest rate, usually 3% above the initial rate). Both tests must be passed, and the lower of the two results determines your maximum loan. This calculator uses the income multiple approach as the primary estimate, with affordability as a secondary check.

The stress test

Since the FCA's Mortgage Market Review in 2014, all regulated lenders must stress-test mortgage applications at a higher rate to ensure borrowers can afford repayments if rates rise. At a 4.5% initial rate with a typical 3% stress buffer, the lender models your ability to pay at 7.5%. If the stressed payment exceeds roughly 45% of your net income, the lender may reduce the loan offered. First-time buyers should factor in that the income multiple displayed may be further constrained by the affordability calculation, particularly at higher loan amounts.

Schemes for first-time buyers

The Lifetime ISA (LISA) offers a 25% government bonus on contributions up to £4,000 per year toward a first home purchase (on properties up to £450,000). The Shared Ownership scheme allows you to buy a share (25–75%) of a property and pay rent on the rest, reducing the deposit and mortgage required. The Mortgage Guarantee Scheme (where available) allows lenders to offer 95% LTV mortgages with government backing. Each scheme has eligibility requirements and trade-offs worth understanding before applying.

Frequently asked questions

The minimum deposit for most high-street mortgages is 5% of the purchase price. At 5% deposit (95% LTV), the mortgage rates available are significantly higher than at 10% or 15% deposit. Most first-time buyers aim for 10% as a minimum to access better rates and reduce monthly payments. A 15% deposit (85% LTV) opens up considerably more competitive deals. Building a larger deposit while property prices rise can feel like a treadmill - using a Lifetime ISA maximises the government bonus on the journey toward a larger deposit.
Yes, significantly. Lenders review your credit file when assessing a mortgage application. A strong credit history with no missed payments, low credit utilisation, and a stable address history demonstrates reliability and typically results in a higher loan offer at a better rate. Defaults, CCJs (County Court Judgments), missed payments, and high credit card utilisation can reduce the loan available or result in a declined application. Check your credit report via Experian, Equifax, or TransUnion before applying and address any errors.
Help to Buy ISAs are closed to new applicants (closed in November 2019) but existing savers can still use the bonus until 2030. You cannot use both a Help to Buy ISA bonus and a Lifetime ISA bonus for the same property purchase - you must choose one. The LISA is generally more generous: up to £1,000 per year government bonus (vs £3,000 maximum lifetime Help to Buy bonus) and no requirement for the solicitor to claim it on your behalf. If you hold both, the LISA bonus is typically the better option for most buyers.