Use our buy‑to‑let remortgage calculator to get a quick, accurate estimate of your monthly mortgage payments, loan‑to‑value (LTV), and potential borrowing levels for a rental property remortgage. Whether you are considering a like-for-like remortgage or exploring equity release for further investment, this calculator allows you to compare repayment types, interest rates, mortgage terms and loan amounts to understand the potential cost of your buy-to-let remortgage.
Enter your property value, current equity amount or loan amount, any additional borrowing required and an interest rate to see how different buy‑to‑let remortgage scenarios could affect your repayments. The calculations are based on standard buy-to-let remortgage structures commonly used by UK lenders, making the results a practical starting point when reviewing remortgage options.
Results
Monthly payment
—
LTV
—
Released equity
—
IMPORTANT: Our buy to let remortgage calculator is designed to give a useful indication of mortgage payments only based on the inputs provided, and does not constitute any form of financial advice. In practice, buy-to-let remortgage affordability is influenced by more than the existing loan balance and interest rate. Lenders will also consider rental income, stress testing assumptions, property value, borrower structure and, where relevant, the purpose of any additional borrowing when assessing a remortgage application. We cannot accept responsibility for errors as a result of using this calculator. Please speak to one of our brokers if you require assistance or further advice.
Understanding Your Buy‑to‑Let Remortgage Results
Once you have run the calculation, your results will show your estimated monthly mortgage payment, your loan-to-value (LTV), and any equity released based on the figures entered. Together, these results provide a useful indication of how your remortgage may affect ongoing costs and borrowing levels.
LTV remains a key factor in buy-to-let remortgaging. Lenders commonly use it to determine product availability, interest rates and affordability criteria. Lower LTV remortgages often provide access to a wider range of mortgage options, while higher LTV borrowing or increased loan sizes may be subject to stricter rental coverage requirements and higher stress rates.
The monthly payment shown reflects the interest rate and term selected in the calculator. However, buy-to-let lenders typically assess affordability using a higher notional or stressed interest rate rather than the pay rate alone. This approach is intended to ensure that rental income remains sufficient if interest rates increase over time. Our buy to let stress test calculator can help you model various scenarios.
This calculator is therefore best used as an initial planning tool. It allows you to compare remortgage scenarios, assess the impact of additional borrowing, and understand how changes in interest rates or loan size may affect projected costs. For a more precise assessment, lenders will also consider rental income, borrower structure, tax position and any existing buy-to-let portfolio exposure.
Worked Buy-to-Let Remortgage Example
To illustrate how the calculator can be used in practice, consider a typical buy-to-let remortgage scenario.
An investor is owns a rental property valued at £400,000, with an existing mortgage balance of £220,000. This represents an existing loan-to-value (LTV) of 55%. The investor wishes to remortgage and raise an additional £40,000 to fund a future property purchase, resulting in a new loan amount of £260,000 and an updated LTV of 65%.
Assuming an interest rate of 5.25% over a 25-year term, the calculator provides an estimated monthly mortgage payment based on the revised borrowing - £962.50 on an interest-only repayment method. In practice, many lenders would assess whether the rental income continues to meet affordability requirements once the additional borrowing is taken into account, often using a stressed interest rate higher than the pay rate. Our rental stress test calculator is also available to model these scenarios further.
This example highlights how changes in property value, loan size and equity release can affect both monthly costs and lender appetite when remortgaging a buy-to-let property.
Lender Insight on Buy-to-Let Remortgaging
When assessing buy-to-let remortgage applications, lenders look beyond the existing mortgage balance. The purpose of any additional borrowing, rental income sustainability and the borrower’s wider portfolio exposure can all influence affordability and product availability. As a result, borrowing outcomes can vary between lenders, even where property value and loan-to-value appear similar on paper.
If you’d like a broader explanation of how buy-to-let mortgages are assessed, including lender criteria, rental stress testing and common structures, our buy-to-let overview provides additional context.
Buy-to-Let Remortgage Calculator FAQs
Does the calculator include rental stress testing?
No. The calculator estimates payments based on the interest rate and term entered. Buy-to-let lenders typically assess affordability using a higher stressed interest rate to confirm that rental income remains sufficient if rates rise. If you'd like to explore stress testing, use our stress testing calculator.
Can I use this calculator to estimate equity release?
Yes. By adjusting the loan amount and property value, the calculator can provide an indication of how much equity may be released from a buy to let investment property. Actual equity release will depend on lender criteria, rental affordability and property type.
Does additional borrowing affect buy-to-let affordability?
Yes. Increasing the loan amount can change loan-to-value (LTV) and rental coverage requirements. Lenders will reassess affordability based on the total borrowing, not just the existing mortgage balance.
Is buy-to-let remortgaging assessed differently for limited companies?
Often, yes. Many lenders apply different stress testing assumptions and rental coverage ratios for limited company buy-to-let remortgages compared with personal ownership.
Will all lenders accept the same remortgage structure?
No. Buy-to-let remortgage criteria vary across the market. Interest rate stress testing, acceptable property types and treatment of additional borrowing can differ significantly between lenders.