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Property financeLast updated: 17 Jul 2026
FREE BUy to let mortgage CALCULATOR
Buy to let mortgage calculator
Our buy to let mortgage calculator gives you an instant estimate of how much you could borrow and what your monthly repayments would look like, so you can see the true cost of a buy to let mortgage before you apply. Whether you're buying your first rental property or adding to an existing portfolio, just enter your loan amount, term and interest rate below to get your numbers.
Buy to let mortgage calculator
Use our buy to let mortgage calculator to estimate how much you could borrow and what your monthly repayments might be. Whether you're investing in your first rental property or expanding your portfolio, our calculator helps you understand the total cost of your buy to let mortgage, including interest.
Mortgages, development and bridging loans for commercial or buy to let properties.
How long do you want to pay back your loan for?
How much do you want to borrow?
£25,000
Interest rate
Typical buy-to-let mortgages range from 7% - 16% APR depending on the duration, amount and lender.
Loan amount
£ -
Total interest amount
£ -
11% APR over 10 years.
Total repayment amount
£ -
Total monthly repayment
£ - / month
Not sure what you can afford?
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What is a buy to let mortgage calculator?
A buy to let mortgage calculator is a free tool that estimates your monthly repayments and the total cost of borrowing against a rental property, letting you test different loan amounts, terms and rates before you commit to anything. If you want the full picture on what a buy to let mortgage is and how it works, read our buy to let mortgage guide.
Because a buy to let mortgage is assessed differently to a residential mortgage, with lenders focused on the rental income the property will generate rather than just your personal or business income, it's worth running the numbers properly before you make an offer on a property. A few minutes with the calculator can save you from underestimating what a rental property will really cost each month, or overestimating how much you can borrow against it.
What determines your buy to let mortgage repayments?
Loan amount
he bigger the loan, the higher your monthly repayment and total interest, all else being equal. Reducing your loan with a bigger deposit brings both down.
Interest rate
Typical buy to let mortgages on the Capitalise panel range from 7% to 16% APR, depending on your loan to value, the lender and how the mortgage is structured. A higher rate increases both your monthly cost and the total interest you'll pay over the term.
Loan term
A longer term lowers your monthly repayment but increases the total interest paid over time. Buy to let mortgages on the Capitalise panel run from 1 to 20 years, so there's plenty of room to find the right balance for your cash flow.
Repayment type
Capital repayment clears the loan by the end of the term, interest only leaves the full balance to repay or refinance. Most buy to let mortgages are arranged on an interest only basis, which the next section covers in detail.
How much rent do I need for a buy to let mortgage?
Most lenders need your expected rent to cover at least 125% of the mortgage interest, calculated at a stress rate that's usually higher than the rate you'll actually pay, which is known as the interest coverage ratio, or ICR. Borrowers in a higher tax bracket, or those applying in their personal name rather than through a limited company, are often asked for 145% cover instead of 125%. Here's the maths on a £150,000 interest only buy to let mortgage, using a typical stress rate of 5.5%.
Basic rate or limited company borrower | Higher rate individual borrower | |
|---|---|---|
ICR required | 125% | 145% |
Annual interest at the 5.5% stress rate | £8,250 | £8,250 |
Rent needed each year | £10,313 | £11,963 |
Rent needed each month | £860 | £997 |
This stress rate is used to test affordability and isn't necessarily the rate you'll actually pay, which is why the rent needed can look higher than a simple calculation against your real interest rate would suggest. If the rent a property can achieve falls short of this figure, you'll usually need a bigger deposit to bring the loan amount, and therefore the interest being tested, down to a level the rent can cover.
Interest only or capital repayment, which costs less?
Interest only
Interest only means a lower monthly repayment, since you're only paying off the interest each month rather than the loan itself. The full loan balance is still owed at the end of the term, so you'll need a plan to repay or refinance it. It's the most common structure for buy to let, since rental income covers the lower monthly cost more easily. On a £200,000 buy to let mortgage at 11% APR over 20 years, interest only costs around £1,833 a month, with the £200,000 still owing at the end.
Capital repayment
Capital repayment means a higher monthly repayment, since each payment clears some of the loan as well as the interest. It clears the loan completely by the end of the term, so there's nothing left to repay or refinance. This suits landlords who want to own the property outright rather than sell or remortgage to clear the balance. On the same £200,000 mortgage, capital repayment costs around £2,064 a month, but you'd owe nothing once the term ends.
What deposit should you expect on a buy to let mortgage?
Most lenders ask for a deposit of at least 25% of the property's value on a buy to let mortgage, meaning the loan to value is typically capped at 75%, though some specialised and tier 2 lenders will go up to 75% where a high street bank might cap you at 65%.
Loan to value | Deposit needed | Who it suits |
|---|---|---|
Up to 65% | 35%+ | Strong applications with a large deposit, often through high street lenders |
Up to 75% | 25%+ | The most common range for portfolio landlords and limited company applications |
Above 75% or complex cases | 25% or less | HMOs, first time landlords, or a shorter trading or credit history |
Looking for something else? Try our other loan calculators
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