Mortgage affordability calculator (UK)

Discover how much you could borrow – and the method we use to determine that amount – with our simple to use affordability calculators.

Bear in mind
Your home could be repossessed if you don't keep up repayments on your mortgage.
You may have to pay an early repayment charge to your existing lender if you remortgage.
Any savings will vary depending on personal circumstances.

Knowing what mortgage you can afford to borrow is the first step in deciding which mortgage type and, ultimately, which deal is most suitable for your circumstances.

We recommend doing this as early as possible in your mortgage application process.

Benefits of using a mortgage loan calculator

  • Learn exactly how much you can afford to pay each month
  • Get a clear oversight of your monthly income and outgoings
  • Plan for the future and budget accordingly
  • Choose a mortgage lender and deal that suits your needs

How do I calculate how much mortgage I can afford to borrow?

Before 2014, mortgage lenders would typically calculate mortgage affordability by looking at your income. In most cases, you’d have been able to borrow between three and five times your annual income.

For example, if your annual income was £45,000, you might have been able to borrow five times that amount – giving you a potential mortgage of up to £225,000.

But in 2014, the now Financial Conduct Authority or FCA (previously known as the Financial Services Authority) published the Mortgage Market Review, which introduced a number of changes to how mortgage affordability is determined.

The most notable change was that mortgage lenders could no longer base their decision solely on the borrower’s income.

How to calculate mortgage affordability

The process of determining affordability now covers the following elements:

1) Your income
Not only does this cover your basic salary, it must also include any income you receive from investments, pensions, or financial support. You’ll need to provide evidence of your income in the form of payslips or accounts, all supported by bank statements.

2) Your outgoings
Your mortgage payments tend to be the largest monthly outgoing, but a lender must also be aware of other outgoings you’re committed to.

This could include credit card repayments, any insurance direct debits, your monthly bills, and other loans you may have.

You might also be asked for estimates relating to your monthly living costs, but this is at the discretion of the lender.

3) A ‘stress test’
This relates to future changes that may impact your ability to afford your monthly mortgage payments. Scenarios the lender might consider are:

  • If you or your partner lost their job
  • If you decided to have children or more children
  • If you or your partner could not work due to illness
  • If interest rates increased or decreased

They do this by taking into account your current lifestyle, along with your income and outgoings, and calculating the possible financial impact of any of these changes.

What if you’re self-employed?

If you’re self-employed, you can often still get a mortgage, though most mortgage lenders will be more cautious than if they were lending to someone working as a full-time employee.

A deposit of at least 5% of the value of the property, a strong credit history, and a track record of a minimum one year (preferably two) of regular work, should help ease any concerns of a mortgage lender.

Find out more about getting a mortgage when you’re self-employed.

Using our mortgage affordability calculator

For a better understanding of what you could afford, try using our straightforward mortgage affordability calculator.

How does a mortgage affordability calculator work? Firstly, you’ll need to answer the following questions:

1) What stage are you at viewing properties?
Let us know what best describes your current situation.

2) What’s the combined income (before tax) of all the mortgage applicants?
This should include all income – including anything on top of your basic salary.

3) How much can you put towards a deposit?
For first time buyers, we recommend between 5% and 20% of the value of the home you’re looking to buy.

Based on your answers, our mortgage affordability calculator will immediately provide you with a figure.

You can then continue to receive your Mortgage in Principle - which you can use to demonstrate to estate agents that you’re a serious buyer - or you can immediately continue to explore your mortgage options.

Bear in mind
Your home could be repossessed if you don't keep up repayments on your mortgage.
You may have to pay an early repayment charge to your existing lender if you remortgage.
Any savings will vary depending on personal circumstances.

Frequently asked questions

How accurate are mortgage affordability calculators?


A mortgage calculator is designed to give you an estimate of what you could afford based on your current circumstances and should be used as guidance only.

For instance, Trussle’s calculator will give you an indication of how much you could borrow, but your lender will still have to carry out a detailed affordability assessment and “stress test” your application to determine what will happen if your financial circumstances change.

Where can I find mortgage affordability calculators?


You can use Trussle’s mortgage calculator, or opt to use a lender’s version.

Lender mortgage affordability calculators include (but aren’t limited to):

  • Halifax mortgage affordability calculator
  • Nationwide mortgage affordability calculator
  • Natwest mortgage affordability calculator
  • Barclays mortgage affordability calculator
  • TSB mortgage affordability calculator

Is a mortgage affordability calculator easy to use?


As long as you have the information to hand, our affordability calculator is quick and easy to use.

You’ll need to know what your income is before tax or the combined income of all the mortgage applicants if you’re buying with someone else, and how much you can put towards a deposit.

Is there a shared ownership mortgage affordability calculator?


Yes, you can find a selection of shared ownership mortgage affordability calculators online.

Shared ownership mortgage calculators tend to estimate how much you’ll need to borrow, what your monthly mortgage payments are likely to be and how much rent you’ll have to pay on the rest of the property.