How much can I borrow?

The tool uses the income-multiple model that lenders use as their first sift. It does three things:

1. Adds your gross annual income to your partner's, if you are applying together.
2. Annualises your monthly credit commitments (multiply by 12) and takes that off the income figure, because a lender will not lend against income that is already spoken for.
3. Multiplies what is left by 4, 4.5 and 5 to give a cautious, typical and generous view of what different lenders might offer.

Gross means before tax and National Insurance. Lenders work from gross income because tax varies by circumstance, and their own models convert it to a net figure internally.

Why there are three numbers, not one

There is no single UK borrowing multiple. Individual lenders set their own, and the spread between the tightest and the most generous on identical circumstances is routinely £40,000 or more. Showing a range is honest; showing one number would not be.

An income multiple is a cap, not a decision. Once you pass it, the lender runs an affordability assessment, and the part that catches most people out is the interest rate stress test.

Regulated UK lenders must consider whether you could still afford the mortgage if interest rates rose during the term. So rather than testing your budget against the rate you are being offered, the lender recalculates the payment at a materially higher rate — usually built from the product's reversion rate plus a margin — and checks that the larger payment still leaves you with enough. If it does not, the loan is cut back until it does.

Last checked August 2026. We do not publish a specific stress rate here because each lender sets its own and they move with the market. Ask the lender or your broker what stress rate they are applying to your case — it is a fair question and they will tell you.

Alongside the stress test, the lender applies an expenditure model. Some of it comes from your bank statements and credit file, and some from national statistical averages for a household of your size. Dependants, childcare, commuting, pension contributions, student loan deductions and any maintenance payments all feed in.

• It is a loan figure, not a property budget. Add your deposit to get the purchase price you can reach, then take off stamp duty, legal fees, survey and moving costs, which come out of the deposit rather than the loan.
• It is not an Agreement in Principle. An AIP is an actual lender's indication based on a credit check. This is arithmetic.
• Variable income is treated far more cautiously than this. Bonus, commission and overtime are often counted at 50% or averaged over several years, and some lenders exclude them entirely.
• Borrowing the maximum is rarely the goal. Passing a stress test is not the same as living comfortably. The number a lender will approve and the number you should take are different questions.
• Term length changes the answer. A longer term lowers the monthly payment, so it can increase the amount that passes affordability — at the cost of a great deal more interest, and lenders will not extend a term beyond your expected retirement without evidence.

Affordability is the single area where broker knowledge is worth the most, because the variation between lenders is enormous and none of it is published in a form you can easily compare. It is worth advice if you are self-employed or a company director; paid partly in bonus, commission or overtime; on a fixed-term or zero-hours contract; using income from more than one job; buying with a gifted deposit or a family member; near retirement age at the end of the term; or if a lender has already declined you.

Being turned down leaves a footprint on your credit file, so a second and third application made blindly can make things worse. A broker's job is to identify a lender whose criteria already fit your circumstances before an application is submitted.