Request Callback
Phil Scott the mortgage centre
Author: Phil Scott -Director
Updated on January 30th, 2024

icon of a house attached to a key
Buy-to-Let Mortgage Calculator

Fill out our quick and easy Buy-to-Let mortgage calculator below. We only require a few details to see how much you may be able to borrow.


What are the benefits of using a Buy-to-Let mortgage calculator?

Having a Buy-to-Let property can be like running your own business, which means you need to pay close attention to all costs. A Buy-to-Let mortgage affordability calculator can be a valuable tool to help you understand how much you could borrow. Simply answer a few questions about your situation and plans, and our calculator will provide a guide on your potential borrowing amount.

This information allows you to plan in detail and ensures you are prepared when applying for a mortgage. It’s important to note that the figure provided by our Buy-to-Let mortgage repayment calculator isn’t exact, as the amount can vary between lenders. Therefore, it’s best to discuss your situation with an expert mortgage adviser.

How do lenders calculate affordability for a Buy-to-Let mortgage?

Assessing affordability is crucial for lenders for two primary reasons. Firstly, it provides them with an essential indication of how much you can afford to borrow, considering that you’ll need to repay them over time. Additionally, it serves as a measure of how profitable your Buy-to-Let property is expected to be, as the rental income is often utilised to cover mortgage payments to the lender.

While residential mortgages typically assess income and outgoings during the affordability assessment, Buy-to-Let mortgage affordability criteria differ slightly. Lenders still consider your income and outgoings, but they also factor in projected rental income. Since interest payments are part of the equation, the rental income should exceed the mortgage interest by a specified margin.

Usually, lenders require the rental income to be anywhere from 125% to 145% of the mortgage interest payment, assuming an interest rate between 5% and 5.5%. It’s advisable to be prepared for higher rates, especially when applying for an HMO Buy-to-Let.

During their assessments, lenders always conduct a stress test to ensure that you can make payments even if interest rates rise. However, if you opt for a fixed-rate mortgage for five years or more, calculations are based on the following:

  • A hike of at least 2% above current rates.
  • Market projections of future interest rates.
  • A minimum stress-test rate of 5% – 5.5%.

What do lenders consider when applying for a Buy-to-Let mortgage?

If you have a property in mind, then you are likely to have an idea of how much rent you will charge. However, lenders won’t take your word for it. Therefore, they will use a surveyor to calculate this based on things such as the property value, market rates and location.

Lenders will also consider any void periods that may arise during ownership to keep things as realistic as possible. Typically, they assume there will be no tenants in the property one month out of the year.

During their affordability calculations, lenders may also factor in property-related expenditure, deducting it from the rental income. This can be costs such as letting agent fees, insurance, safety check costs and any maintenance fees.

Finally, an important consideration is the lenders imposed Loan-to-value (LTC) limit. This is set and will put a cap on how much they will lend. A maximum of 75% is very common for most lenders, although some do offer more.

Always remember that lenders will place their products in LTV tiers. Meaning, if you can provide a larger deposit, you are more likely to receive better interest rates.

Google Logo
4.99 Stars icon
142 Reviews
Proudly working with
… and many more!

Thanks for getting in touch, a member of the team will be in contact shortly.