Our free buy to let mortgage calculator shows how much you could borrow from your rental income, whether the rent passes a lender's rental cover test and what your monthly payments could be on an interest only or repayment basis.
Most buy to let lenders work out the loan amount from the rent rather than your personal income. They want the monthly rent to cover the mortgage interest by 125% to 145% at a stress rate.
Most buy to let mortgages need at least a 25% deposit. With 40% or more you get access to the lowest mortgage rates and more lenders.
Buying a buy to let property usually means paying the additional property surcharge on stamp duty, so factor that into your budget before you make an offer.
Enter the property value, your deposit, the expected monthly rent and an interest rate. The calculator works out your loan amount and loan to value, the maximum loan the rent could support, and your monthly payment on an interest only and a repayment mortgage.
Lenders typically want rental income to cover 125% of the stressed mortgage interest for limited companies and basic rate taxpayers, and 145% for higher rate taxpayers.
Lenders test the mortgage interest at a stress rate, often around 5.5% or the pay rate plus a margin. Five year fixed rates may be tested at the pay rate itself.
Gross yield is the annual rent divided by the purchase price. A £250,000 flat let for £1,250 a month has a gross yield of 6%. Net yield takes off costs like void periods, maintenance and landlord insurance.
If the rent does not quite cover the loan you want, some lenders let you use spare personal income to make up the shortfall.
The figures are a guide only. Each lender sets its own rental cover ratio, stress rate and maximum loan to value, and fees and mortgage rates vary a lot between deals. Rental income is also subject to income tax via Self Assessment, so speak to an accountant about your tax position.
We help landlords with purchases, remortgages and portfolios, whether you buy in your own name or through a limited company. If you have adverse credit, you could be referred to our sister company, Alexander Southwell Mortgages, as this may fall under the specialist category.
Related: Buy to let mortgages · Let to buy mortgages · Stamp duty calculator
Your home may be repossessed if you do not keep up repayments on your mortgage. Written by Jamie Alexander CeMAP, mortgage adviser with 15 years' experience. Last reviewed October 2026.
It depends mainly on the rent. Lenders divide the annual rent by their rental cover ratio and stress rate to find the maximum loan. Some lenders also allow top slicing, using your personal income to support a lower rent.
It is the interest rate a lender uses to test affordability, often higher than the pay rate on your mortgage deal. Five year fixed rates are often tested at a lower stress rate than two year deals.
An interest only basis keeps monthly payments low and maximises cash flow. You still need a plan to repay the loan at the end of the mortgage term, usually by selling the property or remortgaging.
Many landlords use limited companies or special purpose vehicles because of how rental income is taxed. Lenders often use a lower rental cover ratio for companies. Speak to an accountant about the tax side before you decide.
Most buy to let mortgages are not regulated by the FCA. Consumer buy to let, for example when you let a former home to a family member, is regulated, and we can advise on both.
Usually at least 25% of the purchase price, with better rates at 30% to 40% or more.
Some lenders accept first time buyers for buy to let, but choice is limited and you usually need a minimum personal income.
Yes. Landlords often remortgage to a better rate when a fixed rate ends or to release equity for another property.
Whether it is your first buy to let property or your tenth, our mortgage advisers search the market for the right buy to let deal, with no broker fees to pay.
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Fee Free Mortgage Broker is a trading style of Alexander Southwell Mortgage Services Ltd, authorised and regulated by the Financial Conduct Authority (FCA) (FRN 1011890).
Registered in England & Wales (Company No. 11772228).
Registered office: Nix Business Centre, 2 Park Court, Abbey Park Industrial Estate, Romsey, Southampton, SO51 9DH. We are registered with the Information Commissioner’s Office, registration number ZA488146.
Information on this website is for general guidance only and is accurate at the time of writing. It does not constitute personalised financial advice. Mortgage criteria and lender policies can change; please speak to an FCA-authorised adviser for up-to-date advice tailored to your circumstances. Some buy-to-let mortgages are not regulated by the FCA.
Your home may be repossessed if you do not keep up repayments on a mortgage or any other debt secured on it.
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