Who needs the SA105?
You need the SA105 if you received rent or other income from UK land or property and it is above the £1,000 property income allowance. That includes buy-to-let flats, letting a room above the Rent a Room limit, holiday lets, and income such as ground rents or letting land.
If you own a property jointly, you report only your share of the income and expenses.
Key boxes
| Box | What to enter |
|---|---|
| 20 | Total rents and other income from property |
| 20.1 | Property income allowance, if you claim it instead of expenses |
| 24 to 29 | Allowable expenses: rent, rates, insurance, repairs, legal and management costs, services and other costs |
| 37 | Rent a Room exempt amount, if you use Rent a Room relief on a room above the limit |
| 39 | Property losses brought forward from earlier years |
| 42 | Losses set against other income (limited cases) |
| 43 | Losses to carry forward |
| 44 | Residential property finance costs (mortgage interest) |
| 45 | Unused residential finance costs brought forward |
How to complete the SA105 in Self Assessment Software
- Add UK propertyIn Income and reliefs, tick UK property under How you earned.
- Answer For all your UK propertyThis block holds the answers HMRC receives once for all your property: the property income allowance (20.1), cash basis or traditional accounting (20.2), and losses (39, 42, 43). Choose Save answers.
- Add each propertyEnter rents and expenses for each property, or your share if it is jointly owned.
- Add finance costsEnter residential mortgage interest and other finance costs in box 44, not as an expense.
- Check the computationOpen Property tax computation to see the profit and the Finance-cost reducer at 20%.
Allowable property expenses
- Letting agent and management fees.
- Repairs and maintenance, but not improvements.
- Insurance, ground rent and service charges.
- Council tax and utility bills you pay for the tenant.
- Accountancy and legal fees for lets of a year or less.
- Replacing furniture and appliances in a furnished let (replacement, not the first purchase).
You cannot deduct the cost of buying the property or improving it. Those count towards capital gains when you sell. See SA108 capital gains.
Mortgage interest on residential lets
For residential lets you do not deduct mortgage interest from your rental income. Instead you enter it in box 44 and get a tax credit of 20% of the cost. That means higher-rate taxpayers get relief at 20%, not 40%.
The credit cannot be more than the tax on your property profits after the Personal Allowance. Any unused amount carries forward in box 45.
Property losses
If expenses are more than income, you have a property loss. It is usually carried forward and set against future profits from your UK property business. Enter losses from earlier years in box 39 and the loss you carry forward in box 43.
Still stuck?
- Income only from a lodger in your home? Check if Rent a Room relief covers it first.
- Rents of £1,000 or less in total? You may not need the SA105 at all.
- UK property page is complete not ticked? Check each property has rents and the For all your UK property answers are saved.
Still not sorted? Contact us and tell us the page, the tax year and any message you see.
Questions answered
What is the SA105 form?
The SA105 is the UK property page of the Self Assessment return. Landlords use it to report rental income, expenses, finance costs and losses.
Can I deduct mortgage interest from rental income?
Not for residential lets. You enter the interest in box 44 and receive a tax credit of 20% of it instead.
Do I need one SA105 for each property?
No. All your UK property counts as one property business on one SA105, although you can record each property separately while you prepare.
Are furnished holiday lets still separate?
No. The furnished holiday lettings rules ended on 5 April 2025. For 2025-26, holiday lets are part of your ordinary property business.
What if I own a property jointly?
Report only your share of the rent and expenses, usually 50% for a married couple unless you have told HMRC otherwise.
Official sources
These guides explain how HMRC's rules apply in Self Assessment Software. Check GOV.UK for your own circumstances.