How Much Can I Borrow for a Mortgage?
Many UK lenders use around 4 to 4.5 times income as a starting point, but some applicants may qualify for higher multiples. The actual amount you can borrow is ultimately determined by the lender’s affordability assessment and its own lending criteria.
That starting multiple gives you a rough ceiling. The affordability assessment is what actually decides where you land within it, and it’s the part most first-time buyers in Slough underestimate when they start comparing properties before knowing their real budget.
Example: on a salary of £40,000, an indicative 4.5x multiple points to £180,000. Add a £20,000 deposit and that’s an indicative property budget of £200,000. This is only an illustration; a lender could offer less or more once it has assessed your outgoings, debts, dependants, credit history, deposit, and its own criteria. Want your own number instead of someone else’s example? Try our Mortgage Affordability Calculator and adjust the figures to your own income and deposit.
| Gross income | 4.0x | 4.5x | 5.0x |
| £30,000 | £120,000 | £135,000 | £150,000 |
| £40,000 | £160,000 | £180,000 | £200,000 |
| £50,000 | £200,000 | £225,000 | £250,000 |
| £60,000 | £240,000 | £270,000 | £300,000 |
| £75,000 | £300,000 | £337,500 | £375,000 |
Note: Illustrative income-multiple table only, not a mortgage offer or guarantee of what any lender will provide.
How Do Lenders Calculate How Much You Can Borrow?
Lenders start with a loan-to-income cap, then run a full affordability assessment that can reduce, and occasionally increase, the amount that cap suggests.
This works in two stages:
1. Income multiple (loan-to-income cap).
The base figure a lender is willing to consider, calculated as a multiple of your gross annual income. MoneyHelper states borrowing is usually capped at four-and-a-half times annual income, though this isn’t guaranteed and varies by lender and income level. Halifax’s published lending criteria currently show a range from 4.49x for incomes under £40,000 up to 5.50x for some higher earners and eligible first-time buyers, with the exact figure also depending on loan-to-value. Lender criteria change, so check the latest figures before relying on a specific multiple..
2. Affordability assessment.
The lender’s detailed check of whether you can sustain the monthly repayment, based on your outgoings, existing debt, dependants, and credit history. This stage most often reduces the maximum loan below the income-multiple ceiling, and it’s why two people earning the same salary can be offered very different amounts.
Because both stages vary by lender, the same applicant can receive a meaningfully different maximum offer from different lenders, which is why comparing across the market makes a practical difference to how much you can actually borrow.
What Counts as Income for a Mortgage Application?
Lenders count basic salary in full, guaranteed bonus and commission (usually at a reduced percentage), and for self-employed applicants, net profit or a combination of salary and dividends.
For employed applicants, basic salary is used in full. Guaranteed or regular bonus and commission income is usually included too, but often discounted, since lenders want to be confident the income will continue. Overtime is treated similarly: regular, evidenced overtime carries more weight than occasional or unpredictable payments.
Self-employed income is assessed differently, and this is genuinely lender-specific rather than a single industry rule. Sole traders are typically assessed on net profit, while limited company directors are usually assessed on a combination of salary and dividends, though some lenders will also consider retained profits. Evidence requirements (commonly one to three years of accounts or tax returns), and whether a lender uses your latest year’s figure or an average across recent years, vary meaningfully by lender. For the full breakdown of what documents you’ll need and how self-employed income is assessed, see our Self-Employed Borrowers guide.
What Outgoings Reduce Mortgage Affordability?
Lenders check four main factors: monthly outgoings, number of dependants, credit history, and existing financial commitments.
- Monthly outgoings. MoneyHelper confirms lenders weigh up regular spending such as loan and credit card repayments, car finance, childcare costs, and subscriptions when deciding how much they’re willing to offer. For example, a £300 monthly loan or credit commitment reduces the disposable income available for your mortgage costs. The exact impact on your maximum mortgage depends on the lender’s own affordability model, the remaining term of the debt, and your wider financial circumstances, not a fixed pound-for-pound deduction.
- Number of dependants. Children and other financial dependants increase the living costs a lender assumes you’ll have, which reduces the amount available for repayments.
- Credit history. Covered in detail below.
- Existing financial commitments. Other mortgages, guarantor obligations, or maintenance payments are factored in as ongoing outgoings, reducing the maximum loan available.
Each factor feeds into a single affordability figure, which is why the final offer can differ substantially from the initial income-multiple estimate.
How Does Deposit Size Affect How Much You Can Borrow?
A larger deposit does not automatically increase the amount you can borrow, but because it reduces your loan-to-value (LTV) ratio, it can give you access to different lender criteria, products, and interest rates.
Loan-to-value, the proportion of the property’s value you’re borrowing, and affordability are connected but separate. Some lenders apply different maximum income multiples at different LTV bands, so a larger deposit can, for those lenders, unlock a higher borrowing multiple as well as a better rate; for others it will only affect the rate offered, not the multiple. For a full breakdown of deposit sizes and how they affect your options, see our Deposit Guide.
Does Credit History Affect How Much You Can Borrow?
Your credit history can affect which lenders and mortgage products you qualify for, and depending on the nature, severity, and recency of any adverse credit, it can also affect the interest rate, maximum LTV, or amount a lender is prepared to offer.
Credit history isn’t a simple scale where a better score automatically means a larger mortgage. Lenders assess the underlying credit history against their own criteria, and one lender may decline an application over a specific adverse-credit event that another lender accepts. This is why an applicant declined by one lender is sometimes accepted by another at a similar rate. For more on how specific credit issues affect your options, see our Credit Score Guide.
How Much Could a First-Time Buyer Borrow in Slough?
According to the Office for National Statistics and HM Land Registry, first-time buyers in Slough paid an average of £299,000 in May 2026 (provisional), against a South East average of £477,000.
That’s a useful anchor when working out whether a given salary and deposit combination is realistic locally. Using the income-multiple table above, a household income of roughly £60,000 to £70,000 with a 4 to 4.5x multiple lands close to that £299,000 average, before accounting for deposit. ONS data also shows Slough’s average price fell 4.4% year-on-year to £330,000 across all buyer types in May 2026, and that flats in Slough averaged £214,000 against £657,000 for detached properties, so the realistic budget varies considerably by property type. These are area-wide averages, not a guarantee of what you’d pay for a specific property, and they move month to month, so treat them as a starting reference rather than a fixed number.
How Much Can I Borrow vs How Much Should I Borrow?
Qualifying for a maximum loan amount and being able to comfortably afford it are two different questions; the lender’s maximum is a ceiling, not a recommendation.
A lender might offer you £300,000, but that doesn’t automatically mean £300,000 is the right mortgage for you. Beyond the maximum a lender will offer, it’s worth working out: the maximum monthly payment you’d genuinely be comfortable with, your deposit and purchase costs (solicitor fees, survey, stamp duty, moving costs), what you’d want left in savings for emergencies, how a rise in interest rates would affect your payment at renewal, and the mortgage term you’re choosing, since a longer term lowers monthly payments but increases the total interest paid. MoneyHelper makes the same point: affordability tools give a rough estimate, but the right amount for you depends on your income and monthly expenses, not just what a lender is willing to approve.
Can You Increase How Much You’re Able to Borrow?
Three concrete levers exist: reducing existing debt before applying, using a joint application to combine incomes, and increasing your deposit.
- Reducing existing debt before applying. Clearing or reducing credit card balances, loans, or car finance before applying increases your disposable income in the lender’s affordability calculation, which can increase the amount you’re offered, though it isn’t guaranteed.
- Using a joint application to combine incomes. A joint application with a partner combines both incomes into a single affordability assessment, which typically increases the total borrowing amount compared with a sole application, though outgoings and credit history for both applicants are also combined.
- Increasing your deposit. A larger deposit lowers your loan-to-value ratio, which can open up products with higher income multiples at that LTV band, in addition to improving the interest rate.
Why Do Different Lenders Offer Different Amounts?
Lenders calculate affordability differently from one another, so comparing how different lenders assess the same applicant can reveal a materially different maximum offer.
Lenders use different income multiples, different treatment of bonus and self-employed income, and different weightings for outgoings and credit history. This means the same applicant can receive a materially different maximum offer from different lenders. A broker working with first-time buyers in Slough compares these calculations across the market, rather than relying on a single lender’s criteria, to identify which lender is likely to offer the highest amount for your specific circumstances.
Want to know what you could realistically borrow? An affordability assessment gives a more useful figure than applying a standard income multiple on its own. If you’re buying your first home in Slough, a mortgage adviser can compare lender criteria based on your income, deposit, commitments, and circumstances. Visit our First-Time Buyer Mortgages Slough page or book a consultation to get an affordability assessment based on your own numbers.
Important: the information on this page is for general guidance and does not constitute personal mortgage or financial advice. Mortgage lending criteria, affordability calculations, and interest rates vary between lenders and can change. The amount you can borrow will depend on your individual circumstances and the lender’s criteria at the time of application. Speak with a mortgage broker to get an accurate figure for your own situation.
