Many investors and even brokers mistakenly assume that an 80% LTV mortgage automatically results in a higher loan compared to a 75% LTV deal. However, this is not always the case. In fact, the maximum loan amount often depends more on the property’s rental income and the Interest Coverage Ratio (ICR) calculations, rather than just the LTV figure itself.

For 80% LTV buy-to-let mortgages, lenders generally apply stricter affordability tests. These include:

• Higher default stress rates
• Elevated mortgage pay rates
• (Sometimes) higher ICR requirements.

Additional limitations.

• Reduced number of lenders

Because of these constraints, even if the lender allows up to 80% LTV, the actual loan amount could be lower than what is available at 75% LTV, especially when stress-tested using higher pay rates.  

Let’s explore actual lender outcomes based on 5 year fixed rates (as of 26 May 2025) for a Single self contained property valued at £550,000, purchased in a Limited Company across rental incomes from £1,900 to £2,300.

75% LTV Mortgage

• Maximum Loan Possible: £412,500
• Maximum is achieved at lower rent.
• As rental income increases, more lenders become eligible, who will have better terms and reduced fees. Giving a better outcome for the borrower.

80% LTV Mortgage

• Maximum Loan Possible: £440,000
• At same rent levels as for 75%, the maximum loan is less. For the equivalent maximum the rent needs to be higher.
• Maximum achievable for 80%, is only possible at rents of £2,500 or higher.
• Pay rates are also higher for the comparable 75% LTV loans.

Key Insight:

Many 80% LTV products can produce lower loan outcomes than their 75% counterparts at lower rental values due to more conservative affordability assessments and limited number of lenders. 

List of UK Lenders Offering 80% LTV Buy-to-Let Mortgages (2025)

As of May 2025, the following lenders offer up to 80% LTV on buy-to-let mortgages.  Not all will lend to Limited Company purchases:

• Buckinghamshire Building Society
• Cambridge Building Society
• Castle Trust
• Gatehouse Bank
• HSBC
• Kensington Mortgages
• Kent Reliance (KRBS)
• LendInvest
• ModaMortgages
• Molo Finance
• MT Finance
• Newcastle Building Society
• Nottingham Building Society
• Quantum Mortgages
• Suffolk Building Society
• The Mortgage Works (TMW)
• TSB
• United Trust Bank (UTB)
• Vida Homeloans
• Virgin Money
• West One
• Zephyr Homeloans

Use an Advanced BTL Affordability Calculator

To make better-informed decisions, brokers and investors can benefit from using specialist tools like the AxessMax Buy-to-Let Calculator. 

With the AxessMax calculator, you will be able to:

• Calculate the precise Buy-to-Let loan amount for all the lenders listed above – and more! Our system incorporates their specific affordability criteria, real-time stress test rates, and detailed rental income factors to provide you with accurate, up-to-the-minute results.
• Access real-time lender updates: Stay ahead of the curve with daily refreshed rates and criteria.
• Compare 2-year and 5-year fixed-rate results side-by-side: Easily visualize the impact of different product terms on your borrowing.
• Filter results by all types of investment properties: From single units to HMOs and multi-unit blocks, get tailored insights.
• Refine results by client type: Whether you’re an experienced or first-time landlord, dealing with regulated BTL, Expat BTL, or portfolio landlords, our filters ensure relevant results.
• Save invaluable time: Quickly identify suitable lenders and products that meet your specific needs, streamlining your research process.