Updated to fiscal year 2026-27
Mortgage Affordability Calculator
Find out how much you could borrow for a mortgage, based on both the income-multiple cap lenders headline and the affordability check they actually run on your budget.
- The lower cap (your limit)
- The higher cap
| Combined net monthly income | £3,780 |
|---|---|
| Disposable monthly income after living costs and commitments | £2,580 |
| Maximum monthly payment at the stress rate | £2,064 |
| Affordability cap | £337,419 |
| Income-multiple cap | £270,000 |
| Estimated monthly payment at your rate | £1,491 |
| Loan-to-value | 87.1% |
| Income-multiple cap (4.5x £60,000) | £270,000 |
|---|---|
| Affordability cap | £337,419 |
| Limited by | the income multiple |
| Maximum you can borrow | £270,000 |
| Plus your deposit | +£40,000 |
| Maximum property price | £310,000 |
Information
What this calculator does. It estimates how much you could borrow for a mortgage the way a lender decides it: by working out two separate limits and offering you the lower one. The first is the income-multiple cap, a simple multiple of your income (most lenders cap at around 4.5 times). The second is the affordability cap, a check that your budget can cover the payments, tested at a higher interest rate than you would actually pay. Whichever is lower is the most you can borrow.
The income-multiple cap. Lenders will lend up to a fixed multiple of your gross annual income, most commonly 4.5 times, with some reaching 5 to 6 times for higher earners. For a joint mortgage the multiple applies to both incomes added together. This cap does not look at your outgoings or the length of the mortgage: it is purely a multiple of income. It is why banks headline "borrow up to 4.5 times your salary".
The affordability cap. Separately, the lender checks you could still afford the monthly payment if rates rose. It starts from your take-home pay (after income tax and National Insurance), takes off your regular living costs and any existing loan or credit commitments, and treats what is left as the money available for a mortgage. It then works out the largest loan whose payment, calculated at a stressed rate higher than your actual rate, still fits. Because the payment is sized at the stressed rate, the affordability cap is often lower than the headline multiple, especially for lower earners, larger households, or anyone with existing debts. A longer mortgage term lowers the monthly payment, so it raises this cap (it does not change the income-multiple cap). Take-home here is after income tax and National Insurance only, so if you repay a student loan, include its monthly repayment under your commitments; the calculator does not deduct student loan separately.
Why two people can borrow more. Two people earning £45,000 each usually borrow more than one person earning £90,000. Each of them has their own tax-free personal allowance and their own basic-rate band, so their combined take-home pay is higher, which lifts the affordability cap; and the income multiple is applied to both salaries combined.
Your deposit and the property price. The most you can borrow, plus your cash deposit, is the most you can spend on a property. Your deposit's size compared with the price (the loan-to-value) then decides which interest rates you qualify for: a bigger deposit unlocks cheaper rates. This calculator takes the rate as an input rather than working it out from your deposit.
What this calculator does not do. Real lenders estimate your essential living costs from their own models based on official spending data, scaled by household size and where you live. Those models are not published, so we ask you to enter your own monthly living costs instead. Enter a realistic figure for a result that matches how a lender would see you. It also uses one flat income multiple and one flat stress rate that you can adjust; individual lenders vary. The full planner projects your whole financial life forward, so you can see how a mortgage of this size fits alongside your income, savings, and other goals over time.
Sources. MoneyHelper "Mortgage affordability calculator" and "How much can I borrow"; Bank of England Financial Policy Committee, the Loan-to-Income flow limit; FCA "Mortgage lending: responsible lending" (MCOB 11), and the August 2022 withdrawal of the mandated affordability stress rate. Take-home figures use the same HMRC income-tax and National Insurance rules as our PAYE calculator.
FAQ
- How much can I borrow for a mortgage?
Most lenders cap borrowing at around 4.5 times your gross annual income, but they also run an affordability check on your budget and lend the lower of the two. This calculator works out both: the income-multiple cap and the affordability cap, and shows which one limits you. Enter your income, outgoings, and deposit above to see your figure.
- How much can two people borrow together?
For a joint mortgage the income multiple is applied to both salaries combined, and the affordability check uses both take-home pays. Two people earning £45,000 each can usually borrow more than one person earning £90,000, because they have two tax-free personal allowances and two basic-rate bands, so their combined take-home pay is higher. Enter a second income above to model a joint application.
- Why is the affordability calculator giving me less than 4.5 times my salary?
The 4.5-times figure is only one of the two limits. The affordability check, which tests whether your budget can cover the payment at a higher stressed interest rate, is often the lower of the two, especially for lower earners, larger households, or anyone with existing loans. The lender lends the lower cap, so that is your real limit. The bar chart above shows which one is holding you back.
- What is a stress test and why does it lower how much I can borrow?
Lenders check you could still afford the payments if interest rates rose, by sizing the loan against a rate higher than the one you would actually pay. Because the payment is worked out at that higher rate, the loan that "fits" your budget is smaller. Since 2022, lenders set their own stress rate, commonly between 6% and 9%. You can change the assumed stress rate under Advanced options.
- Does a longer mortgage term let me borrow more?
It can raise the affordability cap, because spreading the loan over more years lowers the monthly payment, so a larger loan fits your budget. It does not change the income-multiple cap, which is just a multiple of your income. Try changing the term above to see the effect.
- How do you work out my living costs?
We don't, you tell us. Real lenders estimate your essential spending from their own models based on official ONS data, scaled by household size and region, and those models aren't published. Instead we ask you to enter your own monthly living costs, which is also what the government's MoneyHelper calculator does. Enter a realistic figure covering food, bills, transport, and childcare (but not rent or mortgage) for a result that matches how a lender would see you.
Recent changes
-
Class 1 employee National Insurance was cut to 8%, raising take-home pay and so lifting the affordability cap slightly for a given salary.
-
The FCA withdrew its mandated affordability stress rate (the reversion rate plus 3 percentage points). Lenders now set their own stress rate, so how much you can borrow varies more between lenders than it used to.
-
The Bank of England introduced the Loan-to-Income flow limit, capping the share of new mortgages a lender can write at 4.5 times income or above. This is why 4.5x is the practical ceiling for most borrowers.
Sources
- Mortgage lenders and administrators statistics (Bank of England)
- Income Tax rates and Personal Allowances (HMRC)
- National Insurance rates and categories (HMRC)
- Scottish Income Tax (HMRC)
Disclaimer
Not financial advice. These figures are an estimate based on the inputs you provided and typical lender rules. A real lender assesses your credit history, the specific property, your employment type, and its own essential-cost model, so its offer may differ. The living-cost figure is the one you entered, not a modelled amount. Consult a qualified mortgage adviser or broker before making a decision based on these numbers.
