How much does a £1.5 million mortgage cost?

If you’re considering a £1.5 million mortgage, the headline monthly figure is only part of the story. Your cost will depend on things like:

• the interest rate you’re offered
• the mortgage term (how many years you repay over)
• whether you choose repayment or interest-only
• your deposit and therefore the loan-to-value (LTV)
• how lenders assess affordability for larger borrowing

This guide explains what typically drives the cost of a £1.5 million mortgage and what you’ll want to prepare before you apply.

What will a £1.5 million mortgage cost per month?

Your monthly payment is mainly driven by the interest rate and term length.

In general:

• Longer terms usually reduce monthly repayments, but you may pay more interest overall.
• Higher interest rates increase monthly repayments.
• Repayment mortgages pay off both interest and the balance over time.
• Interest-only mortgages pay only the interest each month, with the capital due later.

Because lenders price mortgages differently and rates can vary by product and borrower profile, it’s best to treat any figures as illustrative until you’ve discussed your options with a broker.

Example monthly repayments for a £1.5 million mortgage (repayment)

Below are illustrative monthly repayment amounts for a £1.5 million mortgage across common term lengths.

These examples assume the interest rate stays the same for the full term. In reality, many borrowers will use fixed or discounted deals and then remortgage or move to a different rate later.

Interest-only vs repayment: which is cheaper each month?

Repayment mortgages

With a repayment mortgage, your monthly payment reduces the loan balance over time. That means your payments are typically higher than interest-only, but the mortgage is designed to be cleared by the end of the term.

Interest-only mortgages

With an interest-only mortgage, you pay only the interest each month. The capital remains outstanding and must be repaid at the end of the term.

For a £1.5 million interest-only mortgage, the monthly interest cost depends on the interest rate, and it’s broadly the same regardless of term length.

Important: Interest-only lending is typically more restricted for large mortgages and lenders will usually want a credible repayment plan for the capital.

How much income do you need for a £1.5 million mortgage?

For affordability, lenders generally assess what you can afford based on your income and your outgoings.

A common approach is to apply an income multiple to estimate borrowing capacity. The exact multiple varies by lender and your circumstances, but it’s often described as being in the region of around 4x to 6x.

To give you a feel for the scale:

• If a lender used a 4x income multiple, £1.5 million would imply income of about £375,000.
• If a lender used a 5x multiple, income would be about £300,000.

However, affordability isn’t just about income. Lenders will also consider:

• your monthly commitments (including loans, credit cards, childcare, maintenance, etc.)
• how much of your income is stable (for example, bonuses and overtime may be treated differently)
• the lender’s stress-testing approach (how they check you can cope if rates rise)

In some cases, borrowers may be asset-rich but income-light, and then an income multiple may not tell the full story.

How much deposit do you need for a £1.5 million mortgage?

Deposit requirements for high-value residential mortgages often depend on the lender’s appetite for risk and the loan-to-value (LTV).

As a broad guide, many lenders look for a deposit somewhere between 10% and 20% for borrowing at this level, but the exact figure can vary.

To illustrate:

• 10% deposit on a £1.5 million property = £150,000
• 20% deposit on a £1.5 million property = £300,000

In practice, lenders may apply tighter LTV limits for higher-value lending, and some will have additional internal rules once the loan size crosses certain thresholds.

A broker can help you understand what LTV you’re likely to be offered and how that impacts monthly repayments.

Eligibility criteria: what lenders typically look at for large mortgages

For larger borrowing, lenders tend to carry out more detailed checks to understand affordability and overall financial position.

In the UK, the Mortgage Market Review (MMR) framework places greater emphasis on ensuring borrowers can afford repayments, including for higher loan amounts.

For many applicants, the key practical points are:

• Higher loan amounts usually trigger more scrutiny.
• If you’re in a high-net-worth category, lenders may take a different approach to assessing affordability, but they will still need evidence and a clear picture of your finances.

While the exact approach varies, you should be prepared to provide a fuller view of:

• income (and how it’s evidenced)
• regular outgoings
• savings and deposit source
• existing debts and commitments
• overall financial position (particularly if you’re relying on assets rather than income)

Can you get a £1.5 million commercial mortgage instead?

Sometimes borrowers need a different type of lending, for example where the property is for business use or investment.

A commercial mortgage may be relevant if the loan is tied to business purposes rather than a standard residential purchase.

Commercial lending can be structured differently and eligibility will depend on factors such as:

• whether the property is owner-occupied or investment/let
• the business’s financial position
• how the lender views the risk of the arrangement

If you’re unsure whether your scenario is residential or commercial, a broker can help you map it to the right lending route.

How a mortgage broker can help with a £1.5 million mortgage

A £1.5 million mortgage is often more complex than a typical high-street application. A specialist broker can help you:

• understand which lenders are likely to consider your LTV and affordability profile
• prepare your application so it aligns with how lenders assess large borrowing
• compare repayment vs interest-only options and the implications for your monthly cost and repayment plan
• reduce delays by ensuring the right documents and evidence are in place

If you want to discuss your options, you can speak to a specialist through our broker service.

Next step

If you’re planning a purchase and want to understand what a £1.5 million mortgage could realistically cost you each month, speak to an expert mortgage broker before you commit.

We can help you review your deposit, income and repayment preferences, and then point you towards the most suitable lending options for your circumstances.