Please compare the two scenarios side by side to see how much your mortgage payments might be if you changed your existing mortgage term, repayment method or interest rate. This can be especially useful if you’re on a variable rate mortgage and want to see the impact of a future change to the Bank of England base rate.

Your current mortgage
Loan part
Current repayment method
Current Actions
Your new mortgage
Loan part
New repayment method
New Actions


How to make a change to your mortgage

If you already have Online Banking, you can start the process to change your mortgage term or the way you repay your mortgage (for example, switching from interest only to repayment) before continuing your application over the phone. Log on, choose your mortgage account, then click ‘Manage my mortgage’.

Changing your term or the way you repay your mortgage 

Before you get in touch with us, please be aware of the following. 

  • If you’re looking to reduce or increase your term or you want to change to an interest-only mortgage, there’s a £75 fee. 
  • A credit search will need to be carried out. 
  • You’ll need to provide evidence of your income.

If you’re changing to an interest only mortgage, we’ll need to see that you have a suitable repayment plan in place to pay off the capital at the end of your term. For example, from a mortgage-related endowment policy or ISA.

If you’re changing your term length, repayment mortgages can run until your intended retirement age or the maximum age of 75. 

For Buy to Let mortgages, the maximum term is 40 years, and the maximum age is 85.

Call us on 0800 051 5579. Lines are open 9am to 7pm Monday to Friday and 9am to 2pm Saturday.

If you are thinking about changing your current deal see the changing deals section for more information.

Important information

This calculator is for illustrative purposes only.  


Santander offers mortgages up to a maximum age of 75. For Interest Only mortgages the maximum age is normally 65. We don’t normally lend past the date you expect to retire.
We’ll always offer you advice when discussing your mortgage requirements. If you know the exact details of the changes you want to make, then you may be able to proceed without advice depending on your circumstances.
If you receive advice from us we’ll ask you about your needs, circumstances and finances to assess whether these changes are affordable before making any changes to your mortgage.
If you make a change to your mortgage you may not be able to revert to your original terms in the future. Any changes will be subject to an affordability assessment and our lending policy at the time.

If you have more than five loan parts please speak to us.