Buy to Let Mortgage Calculator

Buy-to-Let Mortgage Calculator (Interest Only)

Use this interest-only buy-to-let mortgage calculator to estimate the monthly interest cost on a rental-property loan. Adjust the loan amount and interest rate to test how borrowing affects your expected cash flow.

An interest-only payment covers interest, not the capital borrowed. The original loan balance normally remains outstanding and needs a repayment, sale or refinance strategy at the end of the term.

Need to know whether the property stacks up after finance and tax?

We can review your rental income, allowable costs and ownership structure alongside your borrowing.

Discuss your buy-to-let tax position

Rental Expenses: Are You Claiming Everything You Can?

Mortgage costs are only one part of running a rental property. See the top allowable expenses landlords should track, plus dozens more costs that could reduce taxable rental profits.

What's allowable

Buy-to-Let Mortgage Interest Tax Relief Explained

Mortgage interest relief is different for individual landlords and limited companies. Understand the rules for tax credits, their impact on cash flow, and why your ownership structure matters.

Find out more

Limited Company or Personal Buy-to-Let Ownership?

Higher-rate taxpayers often consider a company for new property purchases, but the right route depends on your income, finance plans, portfolio size and whether you need to draw profits personally.

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Buying With a Spouse: Can a Deed of Trust Help?

A Deed of Trust can record unequal beneficial ownership of a jointly owned rental property. For some couples, this may help align rental income with the lower-taxed spouse, subject to the rules.

Find out how

Family Investment Companies for Property Investors

Building a long-term portfolio for your family? A Family Investment Company can be part of a wider succession and inheritance-planning strategy while allowing parents to retain control.

Learn more

Rental Income Not Previously Declared?

The Let Property Campaign gives eligible landlords an opportunity to disclose undeclared rental income to HMRC. Acting before HMRC contacts you can help you manage tax, interest and penalties.

Find out how

The following calculator and commentary are provided solely for informational purposes. Please note that this information may not be current or complete and that it may only apply to certain types of residential properties in the UK. It does not constitute any form of advice.

Property value

Deposit

Deposit %

Interest rate (% per year)

Mortgage term (years)

Amount you need to borrow £240,000

Interest only

£900

per month

Capital + interest

£1,333

per month

Total paid over term (interest only)

£270,000

Total paid over term (capital + interest)

£399,900

Interest-only payments cover interest only; the full loan amount is still owed at the end of the term. Capital and interest payments gradually pay off the loan, so the balance reaches zero by the end of the term. This is an estimate for comparison purposes, not a formal mortgage quote.

60-day reporting deadline:

If any Capital Gains Tax is due on a UK residential property, you must report the sale and pay the tax owed to HMRC within 60 days of completion, using HMRC’s Capital Gains Tax on UK property service. This applies even if you also complete a Self Assessment tax return. Missing the deadline triggers an initial £100 penalty, with further daily and 6 month penalties plus interest if the delay continues. Non-UK residents must report every disposal within 60 days, even where no tax is due.

Please note:

This calculator is designed for individuals selling a UK residential property such as a buy-to-let property. It does not cover limited companies, trusts, personal representatives or UK assets, non-UK residents, or mixed business and residential use. Joint ownership figures assume the interest/disposal being to each named person in their capital shares. For joint owners, HMRC looks at the actual beneficial ownership share, not just what is on the title deeds, and any change to that split normally needs to be agreed and evidenced before the sale. Capital Gains Tax rates and allowances are the same across the whole of the UK, including Scotland and Wales, even though income tax bands differ between countries. This figure is an estimate only; for a full breakdown of how it was calculated, please speak to your adviser.