One of the most common tax planning questions landlords ask is whether it is better to pay off a remaining mortgage or keep the money in savings. The answer is not always as straightforward as it seems. Below is a real-world example to show how the numbers can work in practice.

The starting position – Example

The property has a small outstanding mortgage of £20,000.
Net rental income, after allowable expenses but before tax, is £20,000 per year.
Annual mortgage interest is £1,000.

Under current rules, mortgage interest is not fully deductible. Instead, basic rate tax relief is given.

Income tax on £20,000 rental profit is £1,486.
Mortgage interest tax relief is £200.
Net income tax payable is £1,286.

Option 1: Pay off the mortgage

If the mortgage is fully repaid, rental income remains £20,000.

There is no mortgage interest and therefore no tax relief.
Income tax payable remains £1,486.

Net cash position after tax is £18,514.

Option 2: Keep the mortgage and put £20,000 into savings

The mortgage remains outstanding and mortgage interest is still £1,000 per year.

Income tax before relief is £1,486.
Mortgage interest relief is £200.
Net income tax payable is £1,286.

If the £20,000 is placed into a savings account earning 4% interest, this generates £800 per year in additional income.

Total income before tax is now £20,800.

Comparing the net cashflow

Before paying off the mortgage and putting the money into savings:

Rental income £20,000
Less mortgage interest £1,000
Less tax £1,286
Plus savings interest £800

Net cashflow: £18,514

After paying off the mortgage:

Rental income £20,000
Less tax £1,486

Net cashflow: £18,514

What does this tell us?

In this example, both options result in exactly the same net cash position. Paying off the mortgage does not improve the landlord’s overall cashflow, and keeping the mortgage while earning interest on savings produces an identical outcome.

However, tax planning is not just about the final number. Other factors matter, including interest rate risk, access to cash, future tax bands, savings allowance availability, and personal circumstances.

Key takeaway

There is no one-size-fits-all answer. What looks like an obvious decision financially may not actually make a difference once tax is considered. This is why tailored tax planning is essential before making major financial decisions.

If you are unsure whether to pay off a mortgage, retain borrowing, or restructure your finances, getting personalised advice can help ensure you make the right decision for both tax efficiency and long-term planning.

If you would like a tailored review of your property tax position, feel free to get in touch.