Mortgage Rate Change Calculator UK
This mortgage rate change calculator helps you estimate how much your mortgage payment could increase or decrease when your current fixed deal ends. It is designed for UK homeowners who want to compare their current monthly payment with a projected payment at a new interest rate.
Whether you are preparing for a remortgage, a product transfer, or the possibility of moving onto your lender’s standard variable rate, this tool gives you a practical way to budget ahead.
What this calculator includes
- Current mortgage balance
- Optional property value for extra context
- Current mortgage rate and projected future rate
- Remaining mortgage term in years and months
- Time left on your current deal
- Repayment and interest-only options
- Current payment and projected payment comparison
How it works
The calculator first estimates your current monthly mortgage payment using your remaining balance, current rate and remaining term. It then projects what your balance may be when your current deal ends. Using your estimated future rate and the shortened remaining term, it calculates a new monthly payment so you can compare the difference.
For repayment mortgages, the balance is assumed to reduce during the remainder of the current deal. For interest-only mortgages, the balance is assumed to stay broadly unchanged unless you reduce it separately.
Why your result may be different
This tool is intended for planning, so actual lender figures may differ. Real mortgage payments can vary because of product fees, lender-specific interest calculations, changes in payment dates, overpayments, underpayments, or different follow-on rates.
- Product fees may be paid upfront or added to the mortgage
- Your lender’s standard variable rate may differ from your estimate
- Overpayments can reduce the balance faster than shown
- Different lenders may calculate affordability and pricing differently
Who it’s for
- Homeowners whose fixed deal is ending soon
- Borrowers comparing current and future mortgage costs
- People planning for a remortgage or product transfer
- Anyone stress-testing their budget against a higher rate
Mortgage rate change examples
- A borrower moving from a 2.19% fixed rate to 5.75% may see payments rise sharply even if the balance is lower
- A shorter remaining term can increase payments further when a new deal starts
- An interest-only mortgage may show a smaller change in payment than a repayment mortgage, but the capital still remains outstanding
Important note
This calculator provides estimates only and is not financial, tax, or legal advice. For official figures, check your lender illustration or speak to a qualified adviser.
Use the calculator above to compare your current mortgage payment with a future rate scenario and see how a deal change could affect your monthly budget.