Buy to Let Mortgage Based on Rental Income

Can you get a buy-to-let mortgage based on rental income?

Yes, most buy-to-let mortgages are primarily based on the rental income a property generates rather than your personal salary. This is often referred to as a rental income-based buy-to-let mortgage.

Lenders apply strict calculations to ensure the rent comfortably covers the mortgage, which means understanding their criteria is essential before applying.

Getting the numbers right before applying is essential to avoid delays or declined applications.

Understanding Buy to Let Mortgages

A buy to let mortgage (BTL) is designed for landlords who want to purchase property to rent out.

Unlike residential mortgages, lenders focus primarily on the rental income the property can generate, although some may still require a minimum personal income.

This makes buy-to-let mortgages particularly suited to investors building a property portfolio.

Key Features of Buy To Let Mortgages

Interest Rates

Typically higher than residential mortgages due to the perceived risk to the lender.

Deposits

Usually require a larger deposit, typically 20%–25%, although higher deposits can improve rates depending on how much rent the property will generate and the type of property.

Affordability Assessment

Focused mainly on the rental income potential rather than the borrower’s personal income.

How Rental Income Determines Mortgage Eligibility

Lenders assess buy-to-let mortgages using the property’s expected rental income rather than just your personal earnings.

This is different to residential mortgages, where your personal income is the main factor.

The Role of Rental Income

For a buy-to-let mortgage based on rental income, lenders primarily assess the potential rental yield of the property. This involves a detailed analysis of the local rental market, property type, and expected monthly rent. The expected rent amount is then forecasted by a qualified surveyor. The key metric used by lenders is the Interest Cover Ratio (ICR), which compares the rental income against the mortgage payments.

What is the Interest Coverage Ratio (ICR)?

The key calculation lenders use is the Interest Coverage Ratio (ICR), which determines how much you can borrow.

This measures whether the rental income is enough to cover the mortgage.

Lenders require rental income to comfortably exceed the mortgage payment.

Typically:

• 125% coverage for basic-rate taxpayers
• 140%–145% for higher-rate taxpayers

Lenders also apply a stress test, using a higher interest rate than your actual deal to ensure affordability. This ensures the property remains affordable even if interest rates rise or rental income fluctuates.

Example:

• Mortgage payment (stressed): £500
• Required rent (125%–145%): £625–£725

Each lender applies this differently, so choosing the right one is key.

How much can you borrow based on rental income?

Your borrowing is primarily based on:

• The expected rental income
• The lender’s ICR requirement
• The stress test rate

In simple terms:

• Higher rental income = higher borrowing potential
• Lower rental income = reduced borrowing

This is why choosing the right property can be just as important as choosing the right lender.

Some lenders may also consider your personal income to support the application, known as top slicing. This can increase borrowing where rental income alone is not sufficient.

Types of Buy-to-Let Mortgages

Interest-Only Mortgages

Many landlords choose interest-only mortgages, where monthly payments cover only the interest. This keeps costs lower but requires a repayment strategy at the end.

Repayment Mortgages

Repayment mortgages reduce the loan balance over time but come with higher monthly payments.

Risks and Considerations

Rental fluctuations

Income may vary due to void periods or market changes

Maintenance costs

Ongoing repairs can impact profitability

Tax implications

Rental income is taxable and rules vary depending on ownership structure

Why use a mortgage broker?

Buy-to-let lending criteria varies significantly between lenders.

At Kerr & Watson, we:

• Identify lenders with the most favourable rental calculations
• Structure your application correctly
• Help maximise your borrowing potential
• Avoid delays or declined applications. We work with both high street and specialist lenders to find the best fit for your situation.
  

Want to maximise how much you can borrow?

Speak to Kerr & Watson today and we’ll match you with lenders offering the most favourable rental calculations.

Frequently asked questions about buy-to-let mortgages

Can I get a buy-to-let mortgage without personal income?

Some lenders allow low or no minimum income, but most still require at least £20,000–£25,000.

What rental yield do I need?

This depends on the lender, but rental income must usually cover 125%–145% of the mortgage.

Can first-time landlords get a buy-to-let mortgage?

Yes, although lender choice may be more limited.

Can I use rental income only?

Yes, but some lenders may still factor in your personal financial position this can be known as top slicing.

What is top slicing in buy-to-let mortgages?

Top slicing is where a lender uses your personal income to support borrowing if rental income alone is not sufficient.

Do lenders use actual rent or estimated rent?

Lenders usually rely on a surveyor’s rental valuation rather than the seller’s estimate.

Conclusion

Buy-to-let mortgages based on rental income can offer strong investment opportunities, but lender criteria can vary significantly.

Understanding how rental income is assessed and choosing the right lender is key to securing the best deal.

Need help understanding how much you can borrow?

At Kerr & Watson, we help landlords structure applications correctly and secure the right mortgage based on rental income.

Speak to us today to avoid delays and maximise your borrowing potential.