— Free UK Property Tool —

Mortgage Affordability Calculator

How much mortgage can you afford? Bring income, household spending, savings and purchase costs into one calculation.

Income and repaymentsDeposit and reserveSDLT · LBTT · LTTHigher-rate scenario

Prepared and reviewed by the MMDAI Editorial Team on 16 October 2026 against FCA affordability guidance, HMRC SDLT guidance, Revenue Scotland LBTT guidance and Welsh LTT guidance. Educational estimates only; not personalised financial, legal or tax advice.

Household and purchase

Household budget
£/year

Total annual income before tax. Include only income you expect a lender to accept.

£/month

Your actual monthly income after tax and deductions; entered separately from gross income.

£/month

Exclude rent that ends when you move, debt payments and owner costs entered separately.

£/month

Include loans, cards and other commitments that continue after purchase.

£/month

Council Tax, insurance, service charges and maintenance, excluding the mortgage.

Savings and reserve
£

Cash available for the deposit, tax and costs.

£

This money stays untouched. It cannot exceed your savings.

Mortgage assumptions
%

0–100% is the model range, not a promise that a mortgage product is available.

×

A borrowing assumption, not a universal lender rule. The model range is 1–6×.

%/year

Nominal rate from your own quote or planning assumption; not APRC or a current offer.

percentage points

An editable planning stress. The example is not a mandatory FCA or lender buffer.

years

1–40 whole years in this model. Age, retirement and lender rules may shorten the available term.

Selected home and purchase costs
£

Residential purchase price. The model covers £1,000–£10,000,000.

SDLT in England and Northern Ireland, LBTT in Scotland, LTT in Wales.

Select the treatment that applies at completion. Confirm relief eligibility and replacement-main-home rules with your conveyancer.

Uses the special SDLT residence test, not nationality. This option applies only in England and Northern Ireland.

£

Total cash allowance including VAT and disbursements where applicable.

£

Cash allowance for the survey and valuation costs you pay.

£

Only fees paid in cash. Fees added to the loan are outside this model.

£

Your expected cash cost of moving.

£

Cash required for initial repairs or improvements, separate from your reserve.

How this calculator works — formulas & sources
Borrowing and repayment
Mortgage = smaller of income screen and stressed-budget screen
Income screen = annual gross income × entered multiple

The monthly budget deducts living costs, continuing debts and owner costs from take-home pay. The model uses a capital-and-interest repayment mortgage; the multiple and rate uplift are editable assumptions.

Equal monthly payments
Payment = L × i ÷ [1 − (1 + i)−n]
At zero interest: payment = L ÷ n

L is the mortgage, i the annual rate divided by 1,200, and n the term in months. The higher-rate payment uses the same starting balance and full term, not a later refinance balance.

Deposit, tax and purchase cash
Available cash = savings − reserve
Required cash = deposit + purchase tax + entered upfront costs

The price ceiling satisfies both borrowing and cash limits at exactly the entered deposit percentage. A penny-down search respects jumps in purchase-tax relief. The model does not optimise how much of your savings to use as deposit.

Nation and buyer status
England / Northern Ireland: SDLT
Scotland: LBTT + ADS where applicable
Wales: LTT main or higher residential rates

First-time relief, additional-property treatment and SDLT non-residence use the selected facts. Eligibility, linked purchases, mixed use, trusts, companies, lease-rent NPV and unusual transactions require separate advice. Model price range: £1,000–£10,000,000.

OFFICIAL SOURCES:MoneyHelper — affordability · FCA — rate stress assessment · HMRC — residential SDLT · HMRC — non-resident SDLT · Revenue Scotland — LBTT · Revenue Scotland — ADS · Welsh Government — LTT

Your mortgage budget

Maximum affordable mortgage
—
Monthly payment: —
—
Purchase within your budget
Property price up to—
Deposit at that price—
Cash for deposit, tax and fees—
Repayment checks
Monthly payment after rate uplift—
Monthly budget for the mortgage—
Borrowing screen before cash limits—

—

Selected property
Entered price—
Required mortgage—
Monthly payment on that mortgage—
Purchase tax—
Cash needed for the purchase—

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How it works

What limits your mortgage?

Income, monthly spending and purchase cash all need to work together.

INCOME
Two income figures, two checks

Gross annual income sets the multiple screen. Monthly take-home pay sets the spending budget. Enter both; the calculator does not estimate your tax code or deductions.

SPENDING
Keep the whole household in view

Include regular living costs, debts and owner costs. A payment can fit an income multiple while leaving too little to live on.

CASH
Protect the reserve

Savings must cover more than the deposit. Purchase tax, legal fees, surveys and immediate works use cash too; the reserve stays outside the purchase.

RATES
Test a higher payment

The rate uplift is a planning choice. It tests the same loan and term at a higher rate, without pretending to reproduce every lender’s affordability policy.

TAX
Choose where you are buying

The tax calculation follows the purchase nation and buyer treatment. Scotland and Wales have their own systems, not the England and Northern Ireland SDLT bands.

LIMITS
Use the ceiling as a guide

The ceiling uses exactly your deposit percentage and entered costs. Lender income acceptance, credit history, age, valuation and product availability can reduce real borrowing.

FAQ

Common questions

No. It is an educational repayment model. Lenders also check income stability, credit commitments, age, retirement, dependants, product rules and the property valuation.
The income-multiple screen uses annual gross income. The repayment budget uses actual monthly take-home income after your living costs, debts and owner costs. These are separate constraints.
No. Both are editable planning assumptions. Lenders have their own income and affordability assessments; the example is not a universal legal borrowing limit or mandatory rate buffer.
Yes. Select Scotland for LBTT or Wales for LTT. First-time-buyer treatment and additional-property rules vary. The non-resident option applies only to England and Northern Ireland SDLT.
Green means the selected purchase fits the entered checks. Amber means the borrowing checks pass but purchase cash is short. Red means the borrowing or spending checks fail, or there is no feasible purchase budget. The result shows the relevant shortfall.
Yes. Both calculator links in the UK affordability article transfer all 21 assumptions to this calculator in the same tab. The transfer expires after 30 minutes and is used once.