How Much Can I Borrow? First-Time Buyer Affordability Guide 2026

What Does Affordability Actually Mean?

Lenders don't get a choice about this. Since 26 April 2014, FCA rules have required a lender to show the mortgage is affordable before it lends, using evidence of your income rather than just your word.

How Much Can You Borrow? The Income Multiple Rule

The income multiple is the quick first number. Most lenders cap you at around 4.5 times your gross annual income. Some go to 5 or 5.5 times for higher earners, and a few go to 6 times or more under specific schemes, always with conditions attached.

Here's roughly what that looks like:

If you're buying with someone, lenders usually add your incomes together before applying the multiple. Our guide to joint mortgages covers how that works.

Why do so many lenders stop at 4.5? Partly because the Bank of England wants no more than 15% of new mortgages across the market to be at 4.5 times income or more. From 28 October 2026, individual lenders are allowed to go over that 15% share as long as the market as a whole stays in line. That may mean more lenders offering higher multiples. It's too early to say how many.

As an example, when we checked in October 2026, Nationwide's Helping Hand advertised up to 6 times salary for first time buyers on 5 or 10 year fixes, with conditions. Schemes like that change, so check before you count on one.

How Lenders Calculate What You Can Afford

The multiple sets the upper limit. The lender's affordability model decides where you actually land.

1. Your Income

Here's something that surprises people. The income multiple uses your gross pay, before tax. The affordability check uses what you actually take home, after income tax and National Insurance. The FCA rules say so in black and white.

If you're employed, expect to show recent payslips and often your P60. Self-employed is different, more on that below.

2. Your Existing Debt

Car finance, personal loans, credit cards, buy now pay later, any regular payment you're committed to. The lender takes these off your income before working out what's left for a mortgage.

This is where a lot of borrowing quietly disappears. £250 a month of car finance doesn't sound much. But if a lender tests your mortgage at, say, 7% over 30 years, £250 a month would pay back about £37,500 of mortgage. Every lender's model is different, but that's the idea.

3. Your Outgoings

Lenders look at your regular spending too. Council tax, bills, childcare, travel to work, food, subscriptions. They'll compare what you tell them with your bank statements, and some use typical figures for a household like yours.

Childcare is a big one. Nursery fees for one or two children can make a real dent in what you're offered.

4. Interest Rate Stress Testing

This catches people out. The lender doesn't just check you can pay at the rate you'll be on. It checks you could still pay if rates went up.

Under the FCA rules, a lender has to think about likely interest rates over at least the first five years, and assume they'll rise by at least 1% over that period. How it does that beyond the minimum is up to the lender, so stress rates vary. There used to be a set Bank of England test, 3 percentage points above the rate you'd revert to after your deal, but that was withdrawn from 1 August 2022.

Now the useful bit. That five year stress test doesn't apply if your rate is fixed for five years or more. That's why some lenders will let you borrow a bit more on a five or ten year fix than on a two year deal. But you're tied in for longer, usually with early repayment charges if you want out, so don't pick a longer fix just to get the bigger number.

5. Changes in Your Circumstances

Lenders will ask about anything you can see coming, like a baby on the way or a contract ending next year. If you know about it, tell them.

6. Credit History

Your credit file mostly decides whether you're accepted and by which lenders. Missed payments, defaults or a county court judgment can narrow your choice to specialist lenders, sometimes at higher rates, even when the income side works fine.

The Affordability Check Walkthrough

One person buying alone on £40,000 a year, with £250 a month car finance and nothing else outstanding. This is an illustration, not any lender's actual model.

Clear the car finance first and the same person could get much closer to the full £180,000.

What Counts as Income?

Lenders differ a lot here, which is one reason the same person can get very different answers from two banks.

Income That Lenders Always Accept

• Basic salary from a permanent job, backed up by payslips
• Pension income, if you're already drawing it

Income That Lenders May Scrutinise

• Bonus, commission and overtime. Some lenders count all of it if it's regular, others only part of it, and many want to see a track record
• Self-employed income, usually based on two or three years of figures
• Fixed term contracts and agency work, where some lenders want a history of renewals
• Rental income, which lenders treat very differently

Income That Lenders Usually Won't Count

• Most state benefits, although some lenders accept certain ones, such as child benefit
• Money from family. A gift can go towards your deposit if it's properly documented, but it isn't income
• One off payments, such as redundancy pay or occasional freelance work you can't show is regular

The Deposit Size, How It Affects Your Borrowing

A bigger deposit means you borrow less and usually pay a lower rate. It doesn't usually raise the income multiple, although some higher multiple deals are only available with a bigger deposit.

Our deposit guide goes into the real cost of each.

Understanding Debt-to-Income (DTI) Ratios

You may have read that your total debts, mortgage included, must stay under 45% of your income, and that this is an FCA rule. It isn't. There's no fixed debt-to-income percentage in the UK mortgage rules.

What UK lenders actually do is take your income, knock off your committed payments and living costs, and see whether what's left covers the mortgage at their stress rate. The effect is similar. Every pound going to a loan or card is a pound that can't go to the mortgage.

How Interest Rates Affect Your Affordability

On a £200,000 repayment mortgage over 30 years:

• At 4%, the monthly payment is about £955
• At 5%, it's about £1,074
• At 6%, it's about £1,199

That's around £244 a month between 4% and 6% on exactly the same loan. And because lenders test above the rate you'll pay, a rise in rates hits your maximum borrowing as well as your payment. You can try different rates and terms on our mortgage repayment calculator.

Special Circumstances: Self-Employed Buyers

If you work for yourself, the lender can't look at a payslip. Instead, most want:

• Two or three years of figures, although a few will look at one
• Your SA302 tax calculations and tax year overviews from HMRC, or accounts prepared by an accountant
• For limited company directors, salary and dividends, and with some lenders your share of the company's profit

Many lenders average your last two years. If your income has dropped, some will use the lower year instead.

For more on this, see our Self-Employed Mortgage Guide.

The Role of Credit Checks

When you make a full application, the lender runs a hard credit search. What it's looking for:

• Whether you've paid things on time
• How much you owe, and how close you are to your credit limits
• Defaults, county court judgments, or any bankruptcy or IVA
• How many times you've applied for credit recently

A poor history won't always mean a no, but it often means fewer lenders and higher rates. Our guide to credit scores and mortgages explains what lenders really look at.

What Reduces Your Borrowing Capacity

These are the things that most often knock the figure down:

• Monthly debt payments, especially car finance and personal loans
• Childcare and other big regular costs
• Pay that's mostly overtime, bonus or commission, which some lenders only partly count
• A short mortgage term. The fewer years you have to pay it back, the bigger each payment, and the less you can borrow. Your age can limit the term, see our guide to mortgage age limits
• A small deposit, which means fewer lenders to choose from
• Some property types, such as flats above shops or unusual construction, which some lenders won't touch

What Improves Your Borrowing Capacity

And the things that help:

• Clearing or paying down debts before you apply
• A clean credit file with everything paid on time
• Applying with a partner, so both incomes count
• Steady employment, ideally past any probation period
• A longer term, which lowers the monthly payment, although you'll pay more interest overall
• A fixed rate of five years or more, where the FCA's five year stress test rule doesn't apply

The Affordability Process: Step by Step

1. Work out your own budget. Our affordability calculator is a good place to start.
2. Get an agreement in principle. The lender gives you a rough figure based on what you tell it, plus a credit search.
3. Find the property and make your offer.
4. Full application. Payslips or tax documents, bank statements, a hard credit search and the full affordability check, stress test included.
5. Valuation and offer. The lender values the property and, if it's all fine, issues the mortgage offer.

Common Affordability Mistakes to Avoid

• Taking out car finance or a new credit card in the months before you apply, or while your application is going through
• Changing jobs just before applying, if you can avoid it
• Leaving things off the form. Your bank statements will show your spending anyway, so be upfront from the start
• Counting overtime or bonus as if it were basic pay, when the lender may only count part of it
• Borrowing the maximum just because it's offered

Moving From Affordability to Formal Agreement

Once you know roughly what you can borrow, the next step is an agreement in principle (AIP), sometimes called a decision in principle (DIP). It isn't a mortgage offer, and the full application can still come back with a different number.

To find out more about the AIP and what happens next, see our Complete Agreement in Principle Guide.

The Short Version

• Most lenders cap you at around 4.5 times your income. Some go higher, with conditions.
• The affordability check usually decides the real figure, and it works from your take home pay.
• Monthly debts cut what you can borrow more than most people expect.
• Lenders test you at a higher rate than you'll pay, unless you fix for five years or more.
• The maximum isn't a target.