Fixed-Rate Ending Soon?, Secure your Rate Now

Buy-to-Let Mortgage Calculators

Want to know how much you can borrow for a buy-to-let mortgage? Use our calculator below to find out

Home Mortgage Calculators Buy-to-Let Mortgage Calculators
Pete Mugleston

Author: Pete Mugleston

CeMAP Mortgage Advisor, MD

Updated: July 16, 2025

Working out how much you can borrow for a buy-to-let mortgage can be quite different to the formulas used for residential purchases. Our easy-to-use buy-to-let mortgage calculator below will make things much more straightforward for you.

Buy-to-Let Mortgage Calculator

Our buy-to-let mortgage calculator can show you how much your mortgage could cost you each month and overall. Simply enter the rental property value, deposit, anticipated monthly rent, interest rate, mortgage term and our calculator will do the rest.

Enter the value of the rental property here
£
A deposit of at least 20% is usually required for a buy-to-let mortgage
£
Most lenders will require a deposit of at least 20%
Deposit must be less than the property value
Enter the anticipated monthly rent here
£
Enter the mortgage rate, 5.5% is a typical rate currently but this can vary
%
Enter the mortgage term, 25 years is the average but lenders can offer shorter and longer terms
years
Borrowing

Loan to Value ratio (LTV):

Most lenders won't offer buy-to-let mortgages over a LTV of 80%.

Interest Cover Ratio (ICR):

Most lenders require rental income to be at least 125%-145% of the interest repayments for a buy-to-let mortgage.

Get started with a specialist buy-to-let broker to find out how much they could help you save on your monthly mortgage repayments.

How to calculate affordability and repayments on a buy-to-let mortgage

Whereas affordability for residential mortgages is based on a multiple of your private income, the eligibility criteria for buy-to-let is all about the strength of the property’s investment potential. More specifically, how much rental income can it produce over and above the mortgage payment?

Most lenders expect the monthly rental premium to cover the mortgage repayment by between 125% and 145%. So, for example, if your mortgage repayment is £1,000 per month, then the property’s equivalent rental premium would need to be between £1,250 and £1,450.

So, technically, the amount you can borrow for a buy-to-let mortgage could be far higher than what you might be able to borrow to buy a residential property as long as you have sufficient deposit (minimum 20%) and rental income.

Mortgage Advisor Mortgage Advisor Mortgage Advisor

Get a free consultation from a mortgage advisor today

  • Tailored advice from an expert

  • Get the best deal available for you

  • Save more with our partner services

How this calculator works

Our buy-to-let mortgage calculator is really simple to use.

No personal details are necessary. All you need to input is the following:

  • Purchase price of the property
  • Your deposit amount
  • Proposed monthly rental income (this can be estimated if not yet confirmed)
  • Mortgage interest rate
  • Loan term
  • Use the toggle at the top of the right-hand column to receive calculations for interest-only repayments or capital and interest.

If you’re still quite early in the buying process, you can use the calculator as often as you like and consider many different scenarios. Once ready, speak to a specialist buy-to-let mortgage broker who can look at your requirements in more detail.

We're so confident in our service, we guarantee it.

We know it's important for you to have complete confidence in our service, and trust that you're getting the best chance of mortgage approval at the best available rate. We guarantee to get your mortgage approved where others can't - or we'll give you £100*

Happy approved couple
We Got Approved!

Let-to-buy mortgage calculations

Let-to-buy arrangements effectively involve two separate mortgage requirements –

The calculations will be based on the criteria outlined in the sections above for the buy-to-let mortgage. For the property you’re moving into as your new residential home, the amount you can borrow will be based on a multiple of your annual income. Use our affordability calculator below to see how this could work for you.

Mortgage Affordability Calculator

Use this calculator to determine how much you could potentially borrow for a mortgage, based on the typical salary multiples used by most UK lenders.

Include all income types: salary, bonus, overtime, self-employed, benefits, pensions, maintenance. Even if you've been told it won't count, add it anyway – some lenders are more flexible than others.
£

Based on your total household income, you could borrow up to:

*

4.5x income

This is what most lenders would consider letting you borrow

5x income

Some lenders would consider letting you borrow this amount

6x income

Very few lenders would consider letting you borrow this amount

*To get exact numbers based on your specific income, outgoings, age and other info, you'll need to speak to one of our experts. Lending policies change regularly, so this is purely for illustrative purposes only, and is not tailored financial advice.

Mortgage Advisor Mortgage Advisor Mortgage Advisor

Speak to a mortgage expert about your options

  • Free initial consultation with no obligation
  • A dedicated expert team to handle everything for you
  • Honest, unbiased advice from whole-of-market brokers
  • Expert guidance tailored to your situation
Get Started

Once you’ve seen how much you can borrow, the next step is to see how much the monthly repayments could be for your mortgage. Use our repayment calculator here for a quick snapshot of what these repayments could work out at.

Mortgage Repayment Calculator

This calculator can tell you the monthly and overall cost of your mortgage, based on the loan amount, interest rate, and term length.

Enter the amount you're borrowing
£
Enter the mortgage rate, 5.5% is a typical rate currently but this can vary
%
Enter the mortgage term, 25 years is the average but lenders can offer shorter and longer terms
years

The monthly repayments on a mortgage would be:

Loan amount:
Monthly repayments:
Total to repay:
Total interest:

How interest-only mortgages work:

With an interest-only mortgage, you only pay the interest each month. The original loan amount (the principal) remains unchanged and must be repaid in full at the end of the mortgage term. This means lower monthly payments, but you'll need a repayment plan for the full loan amount.

To get exact numbers based on your specific income, outgoings, age and other info, you'll need to speak to one of our experts. Lending policies change regularly, so this is purely for illustrative purposes only, and is not tailored financial advice.

Mortgage Advisor Mortgage Advisor Mortgage Advisor

Speak to one of our brokers to save money on your monthly repayments

  • Free initial consultation with no obligation
  • A dedicated expert team to handle everything for you
  • Honest, unbiased advice from whole-of-market brokers
  • Expert guidance tailored to your situation
Get Started

What you should do next

Now that you’ve got an idea of how much you could borrow for a buy-to-let property, rather than approaching mortgage lenders directly, the shrewd move is to engage with an experienced mortgage broker who can identify them on your behalf, saving you lots of time and, potentially, some money, too.

Get in touch or call us on 0330 818 7026, and we’ll arrange for a specialist buy-to-let mortgage broker we work with to contact you immediately and discuss your requirements.

FAQs

No, not really – it all depends upon the key requirement of how much rental income the property (or properties) you’re looking to buy can produce. Again, the 125%-145% parameters would need to be hit if you’re using a limited company for the buy-to-let purchase.

The calculations for a commercial buy-to-let mortgage would be broadly similar, and the proposed rental premium would need to be at least equivalent to 125% of the mortgage repayments.

Most, if not all, commercial buy-to-let mortgages are usually only available on an interest-only repayment basis.

Ask us a question

We can help!

We know everyone's circumstances are different, that's why we work with mortgage brokers who are experts in Buy-To-Let mortgages.

Ask us a question and we'll get the best expert to help.

1 of 3
£
£
£
2 of 3
3 of 3

Pete Mugleston

CeMAP Mortgage Advisor, MD

Pete, a CeMAP-qualified mortgage advisor and an expert in all things mortgages, cut his teeth right in the middle of the credit crunch. With plenty of people needing help and few mortgage providers lending, Pete successfully went the extra mile to find mortgages for people whom many others considered lost...

Pete, a CeMAP-qualified mortgage advisor and an expert in all things mortgages, cut his teeth right in the middle of the credit crunch. With plenty of people needing help and few mortgage providers lending, Pete successfully went the extra mile to find mortgages for people whom many others considered lost causes. The experience he gained and his love of helping people reach their goals led him to establish Online Mortgage Advisor, with one clear vision – to help as many customers as possible get the right advice, regardless of need or background.

Pete’s presence in the industry as the ‘go-to’ for specialist finance continues to grow, and he is regularly cited in and writes for both local and national press, as well as trade publications, with a regular column in Mortgage Introducer and being the exclusive mortgage expert for LOVEMoney. Pete also writes for Online Mortgage Advisor of course!

Secure the best mortgage deal for you - Get your free consultation with an expert today