CURRENT POSITION
Day one of the checklist
Affordability looks workable — the checklist is where the work is now. Even self-assessment gives a clearer picture.
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Run the monthly numbers, plan upfront costs, and see where you sit on readiness.
READINESS SUMMARY
0 of 5 readiness factors set; deposit 10%; surplus £2,429
Your deposit clears 10% — moving toward 15% widens lender choice.
Factors set
0 / 5
Deposit %
10%
Surplus
£2,429
DERIVED FROM MONTHLY COSTS
Deposit percentage
10%
Derived from Monthly costs (deposit ÷ property price).
Monthly surplus
£2,429
Derived from Monthly costs (income − mortgage − outgoings).
Tick each as you complete it. These are the non-numeric readiness signals that, alongside affordability, indicate you're in offer-making position.
Tick each factor as you complete it. Even self-assessment gives you a clearer picture of where you stand.
CURRENT POSITION
Affordability looks workable — the checklist is where the work is now. Even self-assessment gives a clearer picture.
NEXT BEST MOVE
Credit check is usually the quickest to complete — it's a free pull and gives an immediate signal.
Where to go next
Tick the factors that apply so we can show your next planning step.
Pro preview
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Open Buyer PlannerTie this check to your full plan
The Buyer Planner connects Affordability Stress Test, Document Readiness, and Conveyancing Dashboard — turning this snapshot into a tracked plan you can return to.
UK mortgage affordability isn’t one number — it’s the combination of three checks lenders run on you:
Online calculators that quote big numbers usually skip the stress test. This calculator factors it in, which is why our number can feel lower than the most generous quotes online but closer to what a lender will actually offer at Agreement in Principle.
The income multiple is the simplest number to grasp and the one most online tools focus on. UK lenders typically apply:
The multiple operates on gross annual income — including basic salary, regular bonuses, commissions, and stable second-income sources. Self-employed buyers usually need 2-3 years of profit history; the lender averages the most recent years.
The affordability assessment is where surprises happen. Lenders deduct the following from your take-home pay when working out how much room there is for a mortgage payment:
The fastest way to increase borrowing capacity is usually paying down credit cards and car finance before applying. Even £200/month of credit commitments translates to roughly £40,000 less borrowing capacity (under a typical affordability model). Six months of clear statements before applying matters more than most buyers realise.
A bigger deposit doesn’t directly increase how much a lender will lend — that’s tied to income. But it unlocks access to lower-LTV mortgage products, which usually carry materially lower rates. Lower rates reduce your stress-test monthly payment, which makes the affordability calculation pass for a higher purchase price.
As a rough guide:
On a £200,000 mortgage, the difference between 95% LTV and 75% LTV rates can be 0.5–1.0% — worth £60–£120/month in repayments, and £18,000–£36,000 over a 25-year mortgage.
Joint mortgages typically increase borrowing capacity by 40–80% over a single applicant on the same income, depending on how the lender treats the second income. Common approaches:
Joint mortgages also share the affordability deduction — your partner’s salary helps absorb existing credit commitments, which can lift borrowing capacity further. The downside is that both applicants’ credit profiles get checked; the weaker profile usually sets the ceiling on what products you qualify for.
Most UK lenders lend 4–4.75x your gross annual income for a first-time buyer, sometimes up to 5x or more for higher earners or specific lender criteria. On a £40,000 salary that's typically £160,000–£200,000. Joint applications usually combine both incomes (sometimes capped at the higher earner + a percentage of the second). Use this calculator to see the realistic borrowing range for your specific income and outgoings.
Three layers: an income multiple (typically 4–4.75x annual income), an affordability assessment that subtracts your committed monthly outgoings from your take-home pay, and a stress test that re-runs the monthly payment at a rate 1–3% higher than the actual product rate. You need to clear all three layers. The income multiple sets the ceiling; the affordability assessment and stress test set the floor below it.
Credit commitments (loans, credit cards, car finance, store cards), regular monthly bills (council tax, utilities, broadband), childcare, child maintenance, and any regular household costs the lender can see on bank statements. Discretionary spending (gym, subscriptions, takeaways) generally isn't deducted but heavy or unusual spending patterns will be queried during underwriting.
Lenders re-run the affordability calculation at a higher interest rate to check you could still afford the mortgage if rates rose. Until 2022 this was usually +3% above the product rate; in 2022 the Bank of England relaxed the mandatory stress test but most lenders still apply +1–3%. The stress test is why your borrowing figure feels lower than online calculators that don't apply one.
Not directly — the borrowing figure is tied to income, not deposit. But a bigger deposit unlocks lower-LTV products with cheaper rates, which can make a higher total purchase price affordable. £200,000 mortgage at 4.5% costs £1,111/month; at 5.5% it's £1,228/month. The £117/month difference can shift what passes the affordability test materially.
Usually yes. Most UK lenders combine both incomes — sometimes adding them at full multiple, sometimes using the higher earner's full multiple plus a percentage of the second. Joint mortgages also share the affordability assessment, so both salaries reduce the deduction for committed outgoings. The result is typically 40-80% more borrowing capacity than a single applicant on the same income.
UK lenders don't publish a single DTI threshold like US lenders do — they use affordability assessments instead. As a working benchmark: total committed credit payments above 20% of gross monthly income typically reduce borrowing capacity meaningfully. Above 40% it gets hard to get a mortgage at all. The fastest way to increase borrowing capacity if you're tight is paying down existing credit, not increasing income.
Yes, but separately from affordability. Credit score affects which products you qualify for (and at what rate); affordability determines how much you can borrow. A poor credit score can shut you out of the cheapest products and push you toward specialist lenders with higher rates — which reduces the headline mortgage you can afford on the same income because the stress test bites harder.
Common rules of thumb: keep total housing costs (mortgage + council tax + utilities + insurance) under 35% of gross income, or under 40% of net income. Lender stress tests bite around these thresholds. Going higher is technically possible but leaves limited buffer for rate rises, life changes, or unexpected expenses. The Readiness Summary tab in this tool checks where your numbers sit.
It's an indicative guide, not a quote. Real lender decisions involve property valuation, full credit check, employment verification, and underwriter discretion. For first-time buyers, calculator outputs are typically within 5–10% of a real Agreement in Principle. Take the calculator figure as a planning range, then get an AIP (free, same day with most lenders) for the actual number.
This calculator is for illustrative purposes only and does not constitute financial or mortgage advice. Actual lender decisions depend on the specific product, property, credit profile and underwriting at the time of application. Speak to an FCA-authorised mortgage broker for advice on your specific case.