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Buying Budget

Mortgage Affordability & Buying Budget Calculator

Estimate only

This is our flagship tool. Enter your income, deposit and monthly commitments and it produces an indicative borrowing range, an estimated property budget, your deposit percentage, loan-to-value and an illustrative monthly repayment.

Affordability varies significantly between lenders. Two lenders looking at identical figures can reach very different answers, because each uses its own income assessment, credit checks, stress rate and policy rules. This illustration shows a typical market position only — it is not a mortgage offer and does not mean you would be approved.

Number of applicants
First-time buyer?

Used for tax relief in the buying-costs tools and for guidance shown here.

Before tax, including reliable regular income.

Total cash you can put towards the purchase, including any gift.

Loans, credit cards, car finance, buy-now-pay-later.

Childcare, maintenance payments, school fees and similar.

An assumption you control. It is not a rate we are offering.

Tax, legal fees, survey and moving costs. Use the buying-costs calculator for a detailed figure.

Estimated property budget

£227,500

Estimated mortgage £202,500 plus £25,000 deposit remaining after upfront costs.

Estimated borrowing range

Estimate only

£180,000 – £213,750

Typical position £202,500 — around 4.5× your income after commitments.

Estimated monthly repayment

£1,183.79

Capital & interest at 5% over 25 years

If rates rose to 7.5%

£1,496.46

Illustrative stress at 7.5%

Deposit percentage

11.0%

Loan-to-value

89.0%

Deposit after upfront costs

£25,000

Payments as share of gross income

31.6%

Estimate only

These figures are an illustration based on the information you provide and the assumptions published below. They are not a mortgage offer, a quotation or advice. Eligibility and affordability are determined by individual lenders. You may wish to compare products or speak to a regulated broker.

How this calculation works

We add the incomes entered, deduct your committed monthly outgoings on an annualised basis, then apply indicative income multiples to produce a borrowing range. A second check limits borrowing so that total housing plus debt costs stay within a set share of gross income at your assumed interest rate — whichever gives the lower figure is used.

Your property budget is the estimated mortgage plus the deposit left after the upfront costs you entered. The monthly repayment uses the standard capital-and-interest formula.

adjusted income = (income₁ + income₂) − (monthly commitments × 12)
borrowing (typical) = min(adjusted income × 4.5, payment ceiling)
payment ceiling = principal supported by ((gross income × 0.45) ÷ 12 − commitments)
monthly payment M = P · r ÷ (1 − (1 + r)^−n)   where r = annual rate ÷ 12, n = term in months

Assumptions

  • Income multiples of 4× to 4.75× income after commitments.
  • Total housing and debt costs capped at 45% of gross income.
  • Default interest rate assumption of 5% and term of 25 years, both editable.
  • A sensitivity view at 7.5% to show how payments change if rates rise.
  • Capital-and-interest (repayment) basis throughout.

Limitations

  • Lenders assess income types differently — bonus, commission, self-employment and benefits may be treated in whole, in part, or not at all.
  • Credit history, account conduct, dependants, job stability and property type all affect real decisions and are not modelled here.
  • No allowance is made for lender-specific stress rates, product fees or maximum age at end of term.
  • The result is not an offer, an agreement in principle, or an indication that you would be accepted.

Sources

Last reviewed: 1 September 2026 · Calculation version 1.0.0

Next in your journey

Mortgage Deposit Calculator

Work out the deposit needed for a target percentage, what you have already, the shortfall, and how long saving might take.

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