Yes they do, most high street banks provide a mortgage calculator on their webpage. By inputting personal data into a mortgage calculator, potential applicants can view the following: How much could they borrow and how much will the mortgage cost. Mortgage calculators are fairly basic, and just provide a rough idea of what is possible; they are no guarantee of a mortgage or a mortgage offer.
To produce a result, users will typically have to enter the following data into a mortgage calculator: How many applicants are applying (sometimes restricted to two); Number of defendants (children and elderly who rely on the applicants for financial support); Annual income (before and after tax); Monthly commitments (loans, student loans, childcare, household spending, lifestyle spending such as club memberships); Mortgage term (most banks advise that the term should end before retirement, due to the reduction in income to repay the mortgage); Property value (that you wish to buy); Applicant deposit (dictates the amount of equity the applicant will have in the property); Mortgage term (to view the cost of the mortgage).
While the above data will be used by the bank to calculate the likelihood of a mortgage application being successfully, more information is considered in the actual application. Each bank will differ in how it calculates its scorecard of eligibility. Things that will impact whether an applicant is successful in the actual mortgage application are: size of the mortgage (is it reasonable in comparison to earnings); how big of a deposit the applicant has (the bigger the better, as there is less risk to the lender); employment status (self employed may find it more difficult to borrow, due to the higher level of unreliability of income); income (the higher the better, especially if the mortgage is low in comparison to the income); credit score (defaults, ccjs will not help, fix any issues if possible); existing debt (impacts the ability to repay the mortgage); electoral roll (usually required to be on it to get a mortgage).
It is crucial to note that mortgage calculators do perform an important role, because a failed mortgage application can be added to a credit score, and can impact the next mortgage application, resulting a spiral of failed applications that may be difficult to remedy. Therefore, aspiring home owners should approach a mortgage application with common sense, and only apply when they are fairly sure it will be successful; a mortgage calculator being a useful tool.
The following UK high street banks have a mortgage calculator (webpage address is subject to change):
Tesco Bank: https://www.tescobank.com/mortgages/mortgage-calculator/
Sainsbury's Bank: https://www.sainsburysbank.co.uk/mortgages/mortgage-calculator
Co-op Bank: https://www.co-operativebank.co.uk/mortgages/mortgage-calculator
Bank of Scotland: https://www.bankofscotland.co.uk/mortgages/mortgage-calculator/
Yorkshire Bank: https://secure.ybonline.co.uk/personal/mortgages/mortgage-calculators/
Post office: https://www.postoffice.co.uk/mortgages/calculator
Chelsea Building Society: https://www.thechelsea.co.uk/mortgages/tools/mortgage-calculators.html