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BTL Max Mortgage
Calculator

Calculate your maximum buy-to-let mortgage amount. Understand your investment property borrowing capacity. Check your LTV ratio with our LTV calculator on this page.

How this calculator works

Enter the expected monthly rent and, where required, the stress rate and interest coverage ratio (ICR). The calculator works out the maximum mortgage amount that would typically be supported by that rent under UK buy-to-let affordability rules. Results are indicative; lenders use their own ICR and criteria.

BTL Max Mortgage Calculator

Buy-to-Let
Borrowing Limits

Buy-to-let mortgages work differently from residential mortgages. Lenders primarily assess affordability based on the expected rental income rather than your personal income, though your earnings are still considered.

Most BTL lenders require the rental income to cover between 125% and 145% of the mortgage payment at a stressed interest rate (typically 5.5% or higher). This rental coverage ratio ensures there's a buffer for void periods and unexpected costs.

BTL lending criteria

125–145%

Rental coverage

Required by most BTL lenders

5.5%+

Stress rate

Rate used for affordability testing

25%

Min deposit

Typical for buy-to-let mortgages

Our BTL mortgage calculator helps you understand the maximum you could borrow based on the expected rent. This is essential for investment planning — knowing your borrowing limit helps you identify suitable properties and calculate potential returns.

Speak to an Expert

Our calculators give you a useful estimate, but your actual mortgage and protection options depend on your full circumstances, credit history and lender criteria. Clearview Mortgage Solutions’ FCA regulated—our CeMAP-qualified advisers are on hand to explain how each calculator applies to you and to help you compare real mortgage quotes from 90+ UK lenders.

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Calculate Your
LTV Ratio

Understanding your loan-to-value ratio helps you find the best mortgage rates. What is LTV? →