How central bank interest rate rises reach your mortgage and savings

What actually changes when a central bank moves interest rates?

When a central bank, like the Bank of England or the European Central Bank, decides to raise or lower interest rates, it's not directly adjusting what you pay on your mortgage. Instead, it changes a single, crucial rate: the one at which commercial banks borrow money from it. This benchmark rate, sometimes called the 'base rate' or 'policy rate', is the foundation of the entire financial system.

Let's say the central bank raises this rate. For commercial banks, it instantly becomes more expensive to borrow the money they need to fund their own lending. To maintain their profit margins and manage their own costs, these banks then typically increase the rates they charge their customers for loans and, usually, the rates they offer on savings.

How does this reach your bank account?

The most immediate impact for many households is often seen in variable-rate mortgages. These loans are directly tied to the central bank's rate, or a rate closely linked to it, so payments can change within weeks or even days of a central bank announcement. If rates go up, so does your monthly payment. For those with fixed-rate mortgages, the change isn't felt until their current fixed term expires and they need to remortgage. At that point, they will face the prevailing, higher rates.

Savings accounts also react, albeit sometimes more slowly. Banks will typically raise the interest they pay on deposits to attract funds, making saving more appealing. Similarly, other forms of borrowing like personal loans, car finance, and credit card rates will tend to climb, making new borrowing more costly and potentially discouraging new spending.

The lag: why it takes time to reach households

This entire process, known as the 'transmission mechanism', doesn't happen overnight. The full force of these changes isn't felt straight away, and this delay is often the least understood part of the story. Economists generally estimate a significant lag between a central bank changing its rates and the full impact being evident in the wider economy – often cited as being anywhere from 12 to 24 months.

One reason for this delay is the prevalence of fixed-rate loans. As mentioned, homeowners on fixed mortgages won't see their payments change until their term ends, which could be several years away for some. Businesses, too, often have existing loans or financing arrangements that aren't immediately affected.

Another factor is consumer behaviour. People don't instantly stop spending or dramatically increase saving the moment rates change. It takes time for the higher cost of borrowing to filter through their budgets, for businesses to adjust their investment plans, and for the overall economic activity to slow down in response to the central bank's actions. This lag is a key challenge for central bankers, as they are making decisions based on economic conditions that might look very different by the time their policy fully takes effect.

Key numbers

Since the start of the current tightening cycle, a major central bank has increased its benchmark rate by a cumulative total of approximately 5 percentage points. This has meant that a household with a typical variable-rate mortgage of an illustrative value might now be paying hundreds more pounds each month than they were before the rate rises began.