The interest rate on a mortgage is the annual percentage the lender charges you for the privilege of borrowing their money. It is applied to your outstanding balance, so as you pay down the capital, the amount of interest you pay each month gradually decreases (on a repayment mortgage). Interest is the main cost of having a mortgage and the single biggest factor in determining your monthly payment.
Mortgage interest rates in the UK vary depending on several factors: the type of product (fixed, tracker, variable), the loan-to-value ratio (lower LTV generally means lower rates), your credit history, the size of the loan, and broader economic conditions including the Bank of England base rate.
It is important to distinguish between the headline interest rate and the APR. The headline rate is just the interest charged on the balance, while the APR also includes mandatory fees. When comparing mortgages, consider both figures, along with the total cost over your intended holding period.
You have a £200,000 mortgage at a 4.5% interest rate on a 25-year repayment basis. In the first month, the interest charged is approximately £750 (4.5% ÷ 12 × £200,000). Your total monthly payment is £1,112, of which £750 is interest and £362 goes toward repaying the capital. Over time, the interest portion decreases and the capital portion increases.
Key Points
- The interest rate is the annual cost of borrowing, applied to your outstanding balance
- Lower LTV ratios generally qualify you for lower interest rates
- The rate type (fixed, tracker, variable) determines whether your rate can change
- Interest is the largest component of your monthly payment, especially in the early years
- The headline rate differs from the APR, which also includes mandatory fees