How to Declare Rental Income to HMRC 2025/26 | AccountingStack

You must declare rental income to HMRC if your total rental income exceeds £1,000 in a tax year. You do this through a Self Assessment tax return, which you must file by 31 January following the end of the tax year. If you have never filed Self Assessment before, you must register by 5 October in the year following your first rental income.

When do you need to register?

If you first received rental income in the 2024/25 tax year (ending 5 April 2025), you must register for Self Assessment by 5 October 2025. Register online at GOV.UK using your National Insurance number and Government Gateway account.

The UK Property supplementary pages

Rental income is reported in the UK Property supplementary pages of your Self Assessment return (SA105). You will need to complete a separate entry for each rental property, or use the "furnished holiday letting" pages if applicable.

Information to have ready for each property:

• Total gross rental income received in the year
• All allowable expenses paid (itemised)
• Mortgage interest paid (for the 20% tax credit calculation)
• Any losses brought forward from previous years
• Details of any capital expenditure (not deductible but may affect CGT later)

Step-by-step: completing the UK Property pages

1. Log in to your Self Assessment account. Go to GOV.UK, log in with your Government Gateway credentials, and select your current year's tax return.
2. Add the UK Property pages. In the "Tailor your return" section, tick "Did you receive any rent or other income from property?" to add the UK Property supplementary pages.
3. Enter your rental income. Enter the total rent received from all UK properties. Do not net this off against expenses at this stage.
4. Enter allowable expenses. Enter each category of expense. The form has specific boxes for different expense types. Enter the full gross figure; HMRC calculates the profit.
5. Enter finance costs (mortgage interest). Enter mortgage interest in the specific "finance costs" box. This is used to calculate your 20% tax credit under Section 24.
6. Review and submit. HMRC calculates your tax due. Review the figures before submitting. Pay by 31 January.

Common mistakes landlords make

• Confusing gross rent with profit and paying tax on the wrong figure
• Forgetting to claim all allowable expenses
• Incorrectly claiming mortgage capital repayments as an expense (only interest is eligible for the tax credit)
• Not declaring income from properties held jointly
• Missing the 5 October registration deadline in the first year
• Failing to declare short-term let income (Airbnb, etc.) alongside standard tenancy income

Rental losses

If your allowable expenses exceed your rental income in a year, you have a rental loss. You cannot offset this loss against other income (such as employment income). Instead, it is carried forward and offset against future rental profits from the same rental business.