Loading today's rates…

Mortgage Calculators & Property Finance Tools

Plan your mortgage before you apply.

Use our free calculators to estimate borrowing, monthly repayments, deposit requirements, loan-to-value, property taxes and buy-to-let returns. Then let Mortgage321 assess the figures against real lender criteria.

Free to use No credit search No registration required Instant results UK mortgage calculations

Calculators give you a starting point. Lender criteria determine the real answer.

Choose a calculator

Pick the question you’re trying to answer — no registration, no credit search, instant results.

Affordability Calculator

How much could I borrow? — Estimate a potential mortgage borrowing range.

Applicant 1
£

Only regular overtime — 50% is used in this illustration.

£

Only regular overtime — 50% is used in this illustration.

50% of regularly received bonus is used in this illustration.

£

50% of regularly received bonus is used in this illustration.

£
£
£

Credit Commitments & Committed Expenditure

Different lenders treat credit commitments and household expenditure differently. These figures are used for illustration only. Where no monthly payment is entered for a credit card, 3% of the outstanding balance is assumed.

No commitments added.

Your Indicative Borrowing Range

Conservative Illustration

£0

Based on approximately 4× the qualifying income used in this illustration.

Indicative max property value with your deposit: £25,000

Higher Income Multiple Illustration

£0

Based on approximately 5× the qualifying income used in this illustration.

Enhanced Borrowing Illustration

£0

Based on approximately 6× the qualifying income used in this illustration.

These are illustrations, not lender affordability results.

Mortgage lenders use their own affordability models and may consider income, expenditure, credit commitments, dependants, mortgage term, interest-rate stress testing, credit profile and other circumstances. A lender may offer more or less than these illustrations.

What does this mean?

This gives you a useful planning range, but it isn't a lender decision. Different lenders may produce materially different maximum borrowing figures from the same income, because each uses its own affordability model.

Assumptions used

  • Applicant 1: Employed income: 100% of basic salary plus 50% of regularly received overtime, bonus, commission and other income.
  • Monthly commitments reduce the illustration by their annual cost multiplied by 5.
  • Credit cards without a stated monthly payment are assumed to cost 3% of the outstanding balance per month.

These are illustrations, not lender affordability results. A lender may offer more or less than the figures shown.

Continue:

General calculator information — including Molly — is not personalised regulated mortgage advice. Figures shown are illustrations, not lender decisions or mortgage offers.

These calculators provide illustrations only and do not constitute financial, investment or tax advice, nor a lender assessment or acceptance decision. Speak to a Mortgage321 adviser for a personalised assessment.

Why might a lender give me a different answer?

Mortgage calculators are useful planning tools, but lenders don’t all assess applications in the same way.

Income Treatment

Not every lender uses every source of income in the same way.

Credit Commitments

Loans, credit cards and other commitments can be treated differently between lenders.

Dependants & Expenditure

Household circumstances and committed expenditure can affect affordability.

Mortgage Term

The proposed term can affect both affordability and monthly repayments.

Credit History

Credit scoring and lender criteria can affect eligibility and borrowing.

Property

The property itself can affect which lenders are prepared to lend.

Two lenders can assess exactly the same applicant and produce very different borrowing figures.

Get My Personalised Mortgage Assessment

Mortgage Calculator FAQs

Short, plain-English answers to the questions we're asked most about the numbers behind a mortgage.

Calculators give you a starting point, not a lender decision. They apply general assumptions — such as income multiples or standard repayment maths — whereas each lender uses its own affordability model, criteria and stress testing. Use them for planning, then have an adviser check the figures against real lender criteria.
It depends on your income, expenditure, credit commitments, dependants, the mortgage term, the property and the lender’s own affordability model — which is why different lenders can produce materially different maximum borrowing figures. Our affordability calculator shows an indicative 4×–6× income range purely for planning.
Lenders don’t all treat income, credit commitments, household expenditure and credit history in the same way, and each applies its own affordability assessment and criteria. Two lenders can assess the same applicant and produce very different figures.
Loan-to-value is the mortgage amount divided by the property value, expressed as a percentage. For example, a £225,000 mortgage on a £300,000 property is 75% LTV. Mortgage products are commonly arranged within maximum LTV bands.
A larger deposit usually means a lower LTV, and products at lower LTV bands are often priced more favourably — but rates change constantly and eligibility always depends on lender criteria. A lower LTV does not guarantee acceptance.
A capital & interest repayment is calculated so the balance reaches zero at the end of the term, using the interest rate entered. With an interest-only mortgage you pay just the interest — the capital balance remains outstanding and requires a suitable repayment strategy.
Many lenders allow overpayments up to an annual allowance — often around 10% of the balance per year — but allowances vary between lenders and products, and early repayment charges may apply if you exceed them. Check your mortgage terms, or ask an adviser to review them for you.
It depends where the property is and the type of purchase. England & Northern Ireland use SDLT, Wales uses Land Transaction Tax (LTT) and Scotland uses Land & Buildings Transaction Tax (LBTT) — each with different bands, first-time buyer rules and additional-property surcharges. Our Property Purchase Tax Calculator shows an indicative figure for your circumstances.
No. A calculator cannot check eligibility or predict a lender’s decision — that depends on the lender’s criteria, affordability assessment, credit scoring and the property. A Mortgage321 assessment can research which lenders may fit before you apply.

A calculator can estimate the numbers. We can assess the lenders.

Mortgage lenders use different affordability models, income calculations and lending criteria. If you’d like to know what your figures could mean in the real mortgage market, Mortgage321 can assess your circumstances and research suitable lenders.

FCA Regulated Whole-of-market Established 2009 4.1 Trustpilot rating