Buy to Let Mortgage Calculator
Enter the price, the deposit, the rate and the rent. See the lender's rental cover test, the largest loan the rent supports and the profit.
The test rate and percentage depend on the lender and on your tax band, so use the figures from your own quote. This is an estimate to help you plan and not advice.
Worked examples
£200,000 property, £1,000 rent
25% deposit, 5% interest only, 5.5% test at 145%
Passes, maximum loan £150,470
The loan is £150,000, interest £625.00 a month, and profit after costs is £2,700 a year.
About Buy to Let Mortgage Calculator
Buy to let lenders mostly decide how much to lend from the rent rather than your salary. They test that the yearly rent covers the interest, worked out at a higher test rate than the one you will pay, by a set percentage. Typical tests are 125% for basic rate taxpayers and 145% for higher rate taxpayers at a test rate of around 5.5%, but the figures differ by lender and by product.
Enter the price, deposit and rent together with your lender's test rate and percentage. The page shows whether the rent passes, the largest loan the rent supports and the highest price that allows with your deposit. It also estimates yearly profit after the mortgage payment, running costs and other costs, the gross rental yield and the return on your deposit. Tax, stamp duty and fees are not included.
How to use Buy to Let Mortgage Calculator
- Enter the property price, your deposit percentage and the monthly rent.
- Enter the mortgage rate and choose interest only or repayment.
- Enter the lender's test rate and the rent cover percentage from your quote.
- Add running costs, then read the test result, the maximum loan and the profit.
Common uses
- Checking if a property will pass a lender's rent test
- Finding the most you can borrow for a given rent
- Estimating the yearly cash profit from a rental
- Comparing interest only and repayment cash flow
Sources
Last reviewed 18 October 2026.
Frequently asked questions
What is the rental cover test?
Lenders require the rent to be a set percentage of the interest at a test rate. At a 145% test and a 5.5% rate, £150,000 of borrowing needs rent of £11,963 a year, which is about £997 a month.
Why do lenders use a higher test rate?
To make sure you could still cover the mortgage if interest rates rise. The test rate is often higher than the rate you pay.
Are the numbers on this page fixed?
No. The test rate and the cover percentage are examples. Use the figures from your lender or broker, because they vary and depend on whether you are a basic or higher rate taxpayer.
What is gross rental yield?
It is the yearly rent divided by the price. Rent of £12,000 on a £200,000 property is a 6% gross yield.
Does the profit include tax?
No. Tax on rental profit, stamp duty surcharges, letting fees and the cost of void periods are not included beyond the running cost percentage you enter.