At first glance, the logic seems simple: the faster you repay your mortgage, the less interest you pay to the lender.

That is why many people buying property in the UK believe that choosing a 15-year mortgage is better than spreading repayments over 25 or 30 years.

However, there is one important consideration: getting a mortgage is only part of the process. You also need to be able to afford the monthly repayments comfortably.

A high monthly mortgage payment can significantly restrict your household budget. If your income temporarily decreases or unexpected expenses arise, managing your financial commitments may become even more difficult.

Let’s look at a practical example to understand how the mortgage term in the UK affects monthly repayments and the overall cost of borrowing.

15-Year vs 30-Year Mortgage: A Practical Example

Imagine you are buying a house worth £250,000.

The purchase details are as follows:

• Property price: £250,000
• 10% deposit: £25,000
• Mortgage amount: £225,000
• Illustrative interest rate: 5.34%

Here is how the monthly repayments would differ depending on the mortgage term.

Mortgage details	30 years	15 years
Mortgage amount	£225,000	£225,000
Interest rate	5.34%	5.34%
Monthly repayment	£1,255	£1,819
Total interest paid	£226,811	£102,490

Illustrative calculations for a repayment mortgage, assuming the interest rate remains at 5.34% throughout the entire term. In practice, interest rates may change, and different mortgage products may have different terms and conditions.

Difference in monthly repayments

£564 per month

Approximately £6,773 more per year in mortgage repayments with a 15-year term.

Over 15 years, you would indeed pay significantly less interest if the same interest rate applied throughout the mortgage term.

But are you prepared to allocate almost £1,820 every month towards your mortgage alone?

Why Is a Shorter Mortgage Term Not Always Better?

In addition to mortgage repayments, most households have other essential expenses, including:

• Utility bills and Council Tax
• Groceries and transport
• Childcare and other expenses related to children
• Insurance, loans and other financial commitments
• Unexpected expenses and personal needs

When a large proportion of your income goes towards your mortgage, you have less financial flexibility.

For example, with a 30-year mortgage, the monthly repayment in our illustration is approximately £1,255. With a 15-year mortgage, it increases to £1,819.

The £564 difference could be used for savings, building an emergency fund or covering other household needs.

Of course, a longer mortgage term generally means paying more interest overall. This is why the right choice depends on your priorities and financial circumstances.

How Does the Mortgage Term Affect Affordability?

When assessing a mortgage application, lenders do not look at your income alone.

They also consider your regular expenses, existing financial commitments, dependants and other factors that may affect your ability to repay the mortgage.

This process is known as an affordability assessment.

For example, an applicant may have sufficient income to qualify for a mortgage with monthly repayments of £1,255 but may not meet the lender’s affordability requirements for repayments of £1,819.

This is why choosing a shorter mortgage term can sometimes limit the amount a lender is prepared to offer.

However, a longer term does not guarantee mortgage approval either. Every lender applies its own affordability criteria.

Can You Take Out a 30-Year Mortgage and Repay It Earlier?

Yes, in many cases this is possible.

In the UK, certain mortgage products allow borrowers to make overpayments, meaning additional payments on top of their required monthly repayments.

For example, some mortgage products allow borrowers to repay up to 10% of their outstanding mortgage balance each year without incurring Early Repayment Charges.

However, this limit is not universal. It depends on the lender, mortgage product and contractual terms.

Making additional payments may help reduce your outstanding mortgage balance, lower the total interest paid and potentially shorten the repayment period.

It is also important to understand how your lender handles overpayments: whether they reduce the mortgage term, recalculate your monthly repayments or apply other restrictions.

Why Can a 30-Year Mortgage Offer Greater Flexibility?

Let’s compare two situations.

Scenario 1. You choose a 15-year mortgage with a required monthly repayment of approximately £1,819.

Even if unexpected expenses arise in a particular month, your contractual mortgage repayment remains the same unless the mortgage terms are changed.

Scenario 2. You choose a 30-year mortgage with a required monthly repayment of approximately £1,255.

During months when your finances allow, you can make additional repayments within the conditions of your mortgage product.

If unexpected expenses arise, you can limit your payments to the required monthly amount.

In this way, a longer mortgage term can provide additional financial flexibility.

However, there is an important consideration: if you do not make overpayments, a 30-year mortgage will generally cost significantly more in total interest.

A longer term also means that your mortgage commitment may continue until later in life.

Which Mortgage Term Is Better: 15, 25 or 30 Years?

There is no universal answer.

A 15-year mortgage may be suitable for someone with a high and stable income, relatively low essential expenses and sufficient savings.

A 25-year or 30-year term may be more comfortable for a household looking to reduce its required monthly repayments and retain more money for other expenses.

When choosing a mortgage term, it is worth considering not only your current income but also potential future changes, such as childcare costs, changing jobs, reduced earnings or approaching retirement.

It is also important to understand that your mortgage term and your fixed-rate period are not the same thing.

For example, you could have a mortgage with a 30-year repayment term but an interest rate fixed for only 2 or 5 years.

Once the fixed-rate period ends, your monthly repayments may change.

The Best Mortgage Term Is One That Works for Your Budget

Wanting to repay your mortgage as quickly as possible is understandable. Generally, the shorter the time you borrow money for, the less interest you pay.

However, when choosing a mortgage term in the UK, it is important to consider not only the total cost of borrowing but also how comfortably the monthly repayments fit into your household budget.

Sometimes, choosing a longer mortgage term and making additional repayments when your financial circumstances allow may be a suitable approach.

In other situations, a shorter mortgage term may be the better option.

The main objective is to find the right balance between your required monthly repayments, the total cost of your mortgage and your household’s financial stability.

All calculations in this article are provided for illustrative purposes only. Actual monthly repayments, available mortgage terms, interest rates and overpayment options depend on the specific mortgage product and the applicant’s individual circumstances.

Your Home (or property) may be repossessed if you do not keep up repayments on your mortgage or any other debts secured on it.

This post is for information purposes only and does not constitute financial or mortgage advice.