Choosing a mortgage in the UK involves more than finding the lowest advertised interest rate.
The type of mortgage you choose can affect your monthly payment, how predictable your costs are, how much flexibility you have and what happens when your initial mortgage deal ends.
The two broad categories most home buyers encounter are fixed-rate mortgages and variable-rate mortgages. Variable mortgages can include tracker, discounted and standard variable rate mortgages.
Understanding the differences can help you ask better questions when comparing mortgage deals.
What Is a UK Mortgage?
A mortgage is a loan used to buy a property.
You borrow money from a lender and repay the mortgage over an agreed period, with interest charged on the outstanding balance.
The property acts as security for the mortgage.
UK mortgages can have different repayment structures, including repayment mortgages and interest-only mortgages. MoneyHelper notes that mortgage terms can range from around 2 to 40 years, depending on the product and borrower circumstances.
What Is a Fixed-Rate Mortgage?
A fixed-rate mortgage keeps the interest rate fixed for the agreed initial deal period.
Common examples include:
- 2-year fixed
- 3-year fixed
- 5-year fixed
- 10-year fixed
For example, if you take a five-year fixed mortgage, the rate is fixed during that five-year deal period according to the mortgage agreement.
This makes monthly budgeting easier because the interest rate doesn’t change with market movements during the fixed period.
MoneyHelper explains that fixed-rate deals can commonly run for two to ten years.
Advantages of a Fixed-Rate Mortgage
Predictable payments
Your mortgage rate remains fixed during the deal period.
Easier budgeting
You can estimate your mortgage payment without worrying about changes in the underlying market rate during the fixed period.
Protection from rate increases
If market rates rise during your fixed period, your agreed fixed rate doesn’t automatically rise.
Disadvantages of a Fixed-Rate Mortgage
You may not benefit from falling rates
If mortgage rates fall after you lock in your fixed deal, you generally continue paying the agreed rate until the fixed period ends.
Early repayment charges may apply
Many fixed mortgages have early repayment charges if you leave the deal early.
The initial rate may be higher
MoneyHelper notes that fixed rates are usually somewhat higher than variable rates, although actual pricing depends on market conditions and individual products.
What Is a Variable-Rate Mortgage?
A variable-rate mortgage is one where the interest rate can change.
Different types include:
- Tracker mortgages
- Discounted-rate mortgages
- Standard variable rate mortgages
The way the rate changes depends on the mortgage agreement.
Variable-rate mortgages can therefore make monthly payments less predictable.
What Is a Tracker Mortgage?
A tracker mortgage normally follows another interest rate, commonly the Bank of England base rate, plus or minus a specified margin.
For example, a hypothetical mortgage might be structured as:
Bank of England base rate + 0.75%
If the underlying rate changes, the mortgage rate generally changes according to the product’s terms.
MoneyHelper says tracker mortgages usually follow the Bank of England base rate plus a specified percentage.
Tracker mortgage advantages
If the tracked rate falls, your mortgage rate may fall as well.
Some tracker products can also provide more flexibility than fixed deals, although the exact terms vary.
Tracker mortgage disadvantages
If the underlying rate increases, your mortgage payment can increase.
That means you need enough room in your budget to handle potential payment changes.
What Is a Standard Variable Rate?
The standard variable rate (SVR) is the lender’s standard mortgage rate.
It can change at the lender’s discretion according to its terms.
SVRs are often higher than introductory mortgage deals.
When an initial fixed or discounted deal ends, borrowers may move onto the lender’s SVR unless they arrange another mortgage deal.
MoneyHelper notes that SVRs are usually higher than other mortgage products and can change at any time.
This is why borrowers should pay attention to the date their initial deal expires.
Fixed vs Variable Mortgage: Key Differences
| Feature | Fixed Rate | Variable Rate |
|---|---|---|
| Interest rate | Fixed during deal | Can change |
| Monthly payment | More predictable | Can rise or fall |
| Benefit from rate cuts | Usually no during fixed period | Potentially yes |
| Exposure to rate increases | Lower during fixed deal | Higher |
| Budgeting | Easier | Less predictable |
| Early repayment charges | Often possible | Depends on product |
| Flexibility | Can be more restricted | Depends on product |
The exact terms always depend on the mortgage agreement.
What Happens When a Fixed Mortgage Ends?
Suppose you take a five-year fixed-rate mortgage.
During those five years, your rate remains fixed.
When the deal ends, you typically need to arrange another mortgage deal or potentially move onto your lender’s SVR.
MoneyHelper notes that the SVR can often be higher, meaning monthly payments may increase if you don’t arrange a new deal.
This makes the end date of your fixed period an important financial deadline.
What Is LTV?
LTV means Loan to Value.
It compares the amount you borrow with the value of the property.
For example:
Property value: £300,000
Mortgage: £240,000
LTV:
£240,000 ÷ £300,000 = 80%
That means the mortgage has an 80% LTV.
The remaining 20% is represented by the deposit, assuming the purchase price and valuation are the same.
MoneyHelper explains that a lower LTV can potentially provide access to lower mortgage rates because the lender is lending a smaller proportion of the property’s value.
How Does Your Deposit Affect Your Mortgage?
A larger deposit generally means you need to borrow less.
For example:
| Property Price | Deposit | Mortgage | Approx. LTV |
|---|---|---|---|
| £300,000 | £30,000 | £270,000 | 90% |
| £300,000 | £60,000 | £240,000 | 80% |
| £300,000 | £90,000 | £210,000 | 70% |
Mortgage pricing can vary considerably between LTV bands.
However, don’t use every pound of your savings for the deposit without considering other home-buying and emergency costs.
What Is APRC?
When comparing mortgage deals, don’t look only at the initial interest rate.
The Annual Percentage Rate of Charge (APRC) is designed to show the annualised cost of a mortgage over its full term, including certain fees and charges.
MoneyHelper recommends comparing APRC as part of assessing mortgage deals.
For example, one mortgage might advertise a lower initial rate but have a large arrangement fee.
Another may have a slightly higher rate but a smaller fee.
The cheaper-looking rate isn’t necessarily the cheaper mortgage overall.
Mortgage Fees to Check
When comparing UK mortgages, check for:
- Arrangement fees
- Product fees
- Valuation fees
- Legal costs
- Broker fees
- Early repayment charges
- Exit fees
- Other administration charges
A mortgage comparison should consider both the interest rate and the fees.
What Are Early Repayment Charges?
An early repayment charge, or ERC, can apply if you repay or leave a mortgage during a period where the lender has specified an early-exit charge.
These charges are particularly relevant with fixed-rate deals.
Before signing, check:
- When the ERC applies
- How it is calculated
- When the ERC ends
- Whether there is an annual overpayment allowance
- Whether you can transfer or port the mortgage
The exact rules depend on the mortgage product.
Can You Overpay a UK Mortgage?
Many mortgages allow borrowers to make additional payments.
MoneyHelper notes that many mortgages allow overpayments, often up to around 10% per year without a fee, although this varies by lender and product.
Overpaying can potentially reduce:
- Outstanding principal
- Future interest
- Mortgage term
But check your mortgage agreement before making a large payment.
If an early repayment charge applies, an overpayment could potentially trigger a fee.
Fixed or Variable: What Should You Compare?
Instead of asking only “Which rate is lower?”, compare:
1. Initial interest rate
What rate will you actually pay?
2. Deal period
How long does the introductory rate last?
3. Monthly payment
Can you comfortably afford it?
4. APRC
What is the broader annualised cost?
5. Fees
How much do you pay upfront?
6. Early repayment charges
What happens if you leave early?
7. Overpayment rules
Can you pay extra without a penalty?
8. Future rate risk
If the mortgage is variable, what could happen if rates increase?
9. Remortgage flexibility
What options will you have when the deal ends?
10. Portability
If you move home, can you transfer the mortgage?
How to Stress-Test a Variable Mortgage
If you’re considering a variable or tracker mortgage, don’t budget only for today’s payment.
Consider hypothetical scenarios.
For example:
Current payment: £1,200/month
What happens if your payment becomes:
£1,300?
£1,400?
£1,500?
The purpose isn’t to predict what rates will do. It’s to understand whether your household budget has enough room for higher payments.
MoneyHelper specifically recommends considering whether you could afford repayments if your interest rate changes.
Questions to Ask a UK Mortgage Adviser
Before choosing a mortgage, ask:
- What is the initial interest rate?
- How long is the deal period?
- What happens after the deal ends?
- What is the lender’s SVR?
- What is the APRC?
- What fees are payable?
- Is there an early repayment charge?
- How much can I overpay?
- Is the mortgage portable?
- What happens if I move home?
- Is the rate fixed, tracker or discounted?
- How could my payment change?
- What happens if rates rise?
- What happens if rates fall?
UK Mortgage Comparison Checklist
Before selecting a mortgage, compare:
- Interest rate
- APRC
- Monthly payment
- Mortgage term
- LTV
- Product fee
- Valuation fee
- Legal costs
- Early repayment charge
- Overpayment allowance
- Portability
- SVR after introductory period
- Remortgage options
Final Thoughts
There isn’t one mortgage structure that works for every UK borrower.
A fixed-rate mortgage provides greater payment predictability during the fixed period, while variable-rate mortgages can move up or down according to their terms and underlying rates.
The key is to compare the complete mortgage package, not just the headline interest rate.
Look at the rate, APRC, fees, deal length, early repayment charges, overpayment rules and what happens when the initial deal expires.
For many borrowers, the most important question is not simply “What is the cheapest rate today?” but rather “How will this mortgage fit my budget under different circumstances?”
This article is for general educational purposes and isn’t mortgage, financial or legal advice. UK mortgage products, rates, eligibility and fees vary by lender and borrower. Scotland, England, Wales and Northern Ireland can also have different property-buying processes.