The SA105 is the UK Property supplementary page to the SA100 tax return. It reports rental income from land and property in the UK, the expenses set against it, the adjusted profit or loss for the year and the residential finance costs that earn a basic-rate tax reduction.
Who completes it
Anyone with income from letting UK land or property, including a room in their own home, a holiday let or a share of a jointly owned property, when that income is more than the £1,000 property allowance or the person chooses to claim expenses instead. Rent a Room relief exempts up to £7,500 a year from letting furnished rooms in your own home. Property owned through a partnership is reported on the partnership’s SA801 instead.
The furnished holiday lettings rules ended on 5 April 2025, so from 2025-26 every UK let is reported in the same section of the page.
What it asks for
- Income: total rents and other income, the number of properties let, tax taken off, premiums for the grant of a lease and reverse premiums.
- Expenses: rent, rates and insurance; repairs and maintenance; non-residential loan interest and finance costs; legal, management and professional fees; costs of services; and other allowable expenses.
- Adjustments: private use, balancing charges, capital allowances, the cost of replacing domestic items, the adjusted profit or loss, losses brought forward and the taxable profit.
- Residential finance costs: mortgage interest and similar costs on residential lets, which are not an expense but give a tax reduction of 20% of the amount, with any unused amount carried forward.
Property losses can only be carried forward against future property profits, not set against other income.
In Tax Optimiser
Add the UK Property (SA105) section; it follows the paper form’s layout. Enter residential finance costs in their own box and the calculation gives the 20% reduction automatically rather than deducting them from profits.
Read more: entering income on a Self Assessment return.
