Mortgage in Principle: What It Is and How to Get One (2026)
A mortgage in principle is a lender's early estimate of how much it might lend you. Learn what an AIP is, how to get…
This how much can I borrow calculator gives you a fast, realistic estimate of the mortgage a UK lender might offer, based on your income, deposit and monthly commitments. Most banks lend somewhere between 4 and 4.5 times your annual income, but the real figure depends on your spending, debts and the lender's stress test.
It is built for first-time buyers, home movers and anyone remortgaging who wants a sensible borrowing ceiling before they start viewing properties or speaking to a broker.
We estimate borrowing at a typical income multiple, then add your deposit for a property budget.
Estimate only. Actual lending depends on credit history, regular outgoings, dependants and each lender's own affordability checks.
You could borrow around
giving a property budget of
The estimated mortgage payment is about of your gross monthly income ().
Rate stress test
at %
at % (+3)
Saved in your browser so you can compare options on your next visit.
At a multiple, with your current deposit added for the budget line.
Based on borrowing at over .
| Year | Interest | Principal | Balance left |
|---|---|---|---|
| Scenario | Borrow | Budget | Monthly | |
|---|---|---|---|---|
Next steps
Mortgage calculator
Monthly payment & interest
Stamp duty
Tax due on the purchase
Take-home pay
Check your net income
Looking for something else? Browse all calculators or read our guides.
Enter your income, any second applicant's income, your deposit and your regular outgoings into the tool above. It returns an estimated maximum loan, the likely property price you could reach, and the income multiple that figure represents. Treat it as a starting point for conversations with a broker, not a formal mortgage offer.
There are two checks every UK lender runs, and a good mortgage affordability calculator mirrors both.
The first is the income multiple. Lenders cap most lending at a multiple of your gross annual income. The common range is:
For a joint application, lenders usually add both incomes, then apply the multiple to the combined figure. The plain formula is:
Maximum loan = total gross annual income × income multiple
The second check is affordability. The lender looks at what is left after tax, National Insurance, existing debts (car finance, loans, credit cards), childcare and other fixed costs, then tests whether you could still pay the mortgage if interest rates rose. This is the stress test, introduced after the financial crisis and overseen by the Financial Conduct Authority. A lender might check you could cope at a rate two or three percentage points above the deal rate. Whichever check produces the lower number, that becomes your ceiling.
Your deposit matters too, because it sets your loan-to-value (LTV). A bigger deposit means a lower LTV, access to better rates, and often a more generous affordability assessment. With a 10% deposit you borrow at 90% LTV; with 25% down you borrow at 75% LTV and unlock cheaper deals.
Say Priya earns £34,000 and her partner Tom earns £30,000. Their combined gross income is £64,000.
Now add a complication. Tom has £280 a month of car finance with two years left. Lenders treat ongoing credit commitments as a reduction in affordable borrowing, so the affordability check might pull their realistic loan down to around £265,000 even though the income multiple alone allowed £288,000. Clearing that car finance before applying could restore much of the gap.
Aisha earns £42,000 and has a £25,000 deposit with no debts.
If Aisha qualifies for a professional or higher-income product at 5×, her loan could rise to £210,000 and her budget to £235,000. That is why it pays to compare a couple of multiples rather than fixing on one number.
Basic salary is counted in full. Beyond that, treatment varies: many lenders count only 50% of regular overtime, commission or bonuses, and some average the last two or three years for self-employed applicants using SA302 tax calculations and accounts. If you are self-employed, lenders typically want two to three years of figures. Our self-employed tax calculator can help you confirm the net profit lenders will assess. Benefits such as Child Benefit and certain tax credits may be partly counted, but policies differ widely.
Once you have a target loan, use the mortgage repayment calculator to see the monthly cost at different rates and terms, so the figure is comfortable and not just approved.
Property tax is regional, so always check the rules for the nation you are buying in rather than assuming England's apply UK-wide.
For impartial, official guidance on mortgages and stress testing, see MoneyHelper and the Financial Conduct Authority. The Bank of England base rate also feeds into the rate your stress test is built on.
These results are estimates for guidance only and are not personal tax or financial advice. Your actual borrowing will depend on a lender's full assessment of your circumstances.
Plan the rest of your purchase with the mortgage calculator, work out your upfront tax with the stamp duty calculator, and if you already own, compare deals using the remortgage calculator.
Most UK lenders cap borrowing at 4 to 4.5 times household income, stretching to 5 times for strong applications. Joint applications combine both incomes.
| Household income | 4x income | 4.5x income | 5x income |
|---|---|---|---|
| £30,000 | £120,000 | £135,000 | £150,000 |
| £45,000 | £180,000 | £202,500 | £225,000 |
| £60,000 | £240,000 | £270,000 | £300,000 |
| £80,000 | £320,000 | £360,000 | £400,000 |
Deposits, credit history and outgoings all move the answer. Free guidance: MoneyHelper mortgage affordability.
This answers the question that comes first: given what you earn and what you have saved, roughly what size of mortgage is realistic? Lenders start from a multiple of income, so this gives you a sensible price range to search within before you fall in love with a house you cannot finance.
It takes a second applicant’s income because most lenders assess joint applications on combined income, and it takes your deposit because the deposit plus the borrowing is what sets your ceiling. Once you have a target price, the mortgage calculator turns it into a monthly payment.
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