Most landlords must file a Self Assessment tax return once their gross rental income tops £1,000 a year. You report the letting on the SA105 UK property pages, work out the profit, and pay Income Tax on it. If you are new to Self Assessment, register with HMRC by 5 October after the tax year ends.
This guide walks a real return end to end: what to declare, which expenses you can and cannot claim, how the Section 24 mortgage interest rules actually bite, and a full worked example for the 2025/26 return (the one due online by 31 January 2027). Every figure here was checked against gov.uk on 17 September 2026.
Do landlords need to file a Self Assessment tax return?
You must file a Self Assessment return once your gross rental income is more than £1,000 in a tax year, or your rental profit means you owe tax. Below £1,000 the property allowance usually covers you and there is nothing to report. Register with HMRC by 5 October following the tax year if you have not filed before.
In practice you report rental income through Self Assessment when any of these apply, per HMRC's guidance on paying tax when you rent out a property:
- your gross rents are above £1,000 a year (the property allowance threshold);
- your rental profit after allowable expenses leaves tax to pay;
- you already file a return for other reasons, such as self-employment or dividends.
If you are letting for the first time, our guide to registering as a landlord for Self Assessment covers how to get your Unique Taxpayer Reference in time for the deadline.
Which tax return does a landlord fill in?
A landlord completes the main SA100 tax return plus the SA105 UK property supplementary pages. The SA105 captures your total rents, your allowable running costs, and, in a separate box, your residential mortgage interest. You file online by 31 January, or on paper by 31 October, after the tax year ends.
The layout matters because of how mortgage interest is now treated. You enter your total rents in the income section, your day-to-day running costs as allowable expenses, and your mortgage and other finance interest in the separate residential finance costs box. That box does not reduce your profit; it feeds a basic-rate tax reduction instead, which is the heart of the worked example below. You can download the current form from HMRC's SA105 UK property page.
Worked example: a higher-rate landlord's 2025/26 return
Meet Priya, an employed higher-rate taxpayer who lets one flat. Her 2025/26 return, due online by 31 January 2027, shows £15,600 of rent, £4,900 of allowable expenses and £7,200 of mortgage interest. Because of Section 24, that interest no longer reduces her profit directly; it gives a 20% tax reduction instead. Here is how the numbers fall out.
Step 1: work out rental income and allowable expenses
Priya first nets her running costs off her rents. Crucially, the mortgage interest is not in this list, it is handled separately at Step 2.
| 2025/26 UK property pages | Amount |
|---|---|
| Rent received (£1,300 x 12) | £15,600 |
| Letting agent fees (10%) | (£1,560) |
| Landlord insurance | (£320) |
| Repairs and maintenance | (£1,120) |
| Service charge and ground rent | (£1,400) |
| Safety certificates and other costs | (£500) |
| Taxable rental profit | £10,700 |
Her taxable property profit is £15,600 minus £4,900 = £10,700. Note the mortgage interest of £7,200 is nowhere in this calculation, that is the whole point of the post-2020 rules.
Step 2: apply the Section 24 mortgage interest tax reduction
Since April 2020, residential landlords cannot deduct mortgage interest from rental profit. Instead you get a basic-rate (20%) tax reduction on the lower of your finance costs, your property profit, or your income above the personal allowance, as HMRC sets out in its worked case studies on residential landlord tax relief. For Priya the lowest of these is her £7,200 interest, so her tax reduction is 20% x £7,200 = £1,440. Our detailed guide to Section 24 landlord tax explains the restriction in full, and the mechanics of mortgage interest tax relief for landlords in more depth.
Step 3: the final tax figure
As a higher-rate taxpayer, Priya's £10,700 profit sits on top of her salary and is taxed at 40%, giving £4,280. She then subtracts the £1,440 Section 24 reduction, leaving £2,840 of tax on her rental profit. Rental income carries no National Insurance, so that is the whole bill on the property.
| Priya's 2025/26 property tax | Amount |
|---|---|
| Taxable rental profit | £10,700 |
| Income Tax at 40% | £4,280 |
| Less Section 24 tax reduction (20% x £7,200) | (£1,440) |
| Tax due on rental profit | £2,840 |
Under the old pre-2017 rules Priya could have deducted the full £7,200 interest, leaving a £3,500 profit taxed at 40%, a £1,400 bill. Section 24 therefore costs her an extra £1,440 a year, because higher-rate landlords now get relief at 20% rather than 40% on their interest. A basic-rate landlord is broadly unaffected, unless adding the interest back to profit tips their total income over the £50,270 higher-rate threshold.
What expenses can a landlord claim on a tax return?
Landlords can deduct the day-to-day running costs of letting a property: letting-agent fees, repairs and maintenance, landlord insurance, ground rent and service charges, utilities or council tax you pay, and accountancy fees. You cannot deduct capital costs such as buying the property, or improving it beyond its original condition. The test is revenue versus capital.
| Usually allowable (revenue) | Not allowable (capital or private) |
|---|---|
| Letting agent and management fees | The purchase price of the property |
| Repairs to restore the original condition | Improvements and extensions |
| Landlord insurance | Mortgage capital repayments |
| Ground rent, service charges, cleaning | Your own time or private costs |
| Accountancy and professional fees | Mortgage interest (relief given at 20% instead) |
Replacing a broken appliance or worn carpet can be claimed under a separate relief rather than as a repair, explained in our guide to replacement of domestic items relief. For the full list, see our breakdown of landlord allowable expenses, and use our landlord tax return checklist to gather everything before you file.
How does the £1,000 property allowance work?
The property allowance lets you earn £1,000 of gross rental income tax-free each year. If your rents are £1,000 or less, you usually have nothing to report. Above that, you can either deduct the £1,000 allowance instead of your actual expenses, or claim your real costs, whichever leaves you paying less tax.
The allowance is an either/or choice: you take the flat £1,000 or your actual expenses, never both, as set out in HMRC's guidance on tax-free property and trading allowances. It suits landlords with very low running costs, a room or a driveway let cheaply, for example. A landlord like Priya, with £4,900 of real expenses, is far better off claiming actual costs. Our comparison of the £1,000 property allowance versus expenses shows where the line falls.
Do landlords pay National Insurance on rental income?
No. Rental income from letting property is treated as investment income, not trading income, so it carries no Class 2 or Class 4 National Insurance. You pay only Income Tax on the profit. The rare exception is running property as a genuine business with substantial services, such as a guest house, where NIC can apply.
How do landlords split rental income on a jointly owned property?
Where a property is owned jointly by a married couple or civil partners, HMRC taxes the rental profit 50/50 by default, whatever the actual ownership shares, unless you file a Form 17 declaration reflecting the real beneficial split. Unmarried joint owners are taxed on their actual share. Splitting income toward the lower earner can cut the household's tax, and for larger portfolios some landlords weigh incorporating, covered in our guide to owning property through a limited company versus personally.
What are the Self Assessment deadlines for landlords?
For the 2025/26 tax year, register for Self Assessment by 5 October 2026 if you are new, file a paper return by 31 October 2026 or an online return by 31 January 2027, and pay any tax due by 31 January 2027. Payments on account may also fall due alongside the balance.
| 2025/26 landlord deadline | Date |
|---|---|
| Register for Self Assessment (new landlords) | 5 October 2026 |
| Paper tax return | 31 October 2026 |
| Online tax return | 31 January 2027 |
| Pay the tax you owe (and first payment on account) | 31 January 2027 |
| Second payment on account | 31 July 2027 |
If your Self Assessment bill is more than £1,000 and less than 80% of your tax is collected at source, HMRC asks for payments on account, two advance instalments toward next year's bill, as explained in HMRC's guidance on payments on account. That is why a first landlord tax bill can feel unexpectedly large, our note on why your first tax bill is so high breaks it down. When it is time to pay, see how to pay your Self Assessment tax bill, and check the full Self Assessment filing deadline guide so you never miss one.
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Property tax has more traps than most, the Section 24 restriction, the revenue-versus-capital line, and payments on account together catch out plenty of landlords. If you would rather hand the SA105 to someone who files them every week, our accountants for landlords and dedicated Self Assessment service will prepare, check and submit your return for a fixed fee. Book a free call and we will make sure every allowable cost is claimed and every deadline met.
Frequently asked questions
How do I report rental income on a Self Assessment tax return?
You report rental income on the SA105 UK property pages, filed with your main SA100 return. Enter your total rents, deduct your allowable running costs to reach the profit, and put your mortgage interest in the separate residential finance costs box, which gives a 20% tax reduction rather than reducing profit. File online by 31 January after the tax year.
How does Section 24 mortgage interest relief work for landlords?
Since April 2020, residential landlords cannot deduct mortgage interest from rental profit. Instead you receive a basic-rate tax reduction worth 20% of the lower of your finance costs, your property profit, or your income above the personal allowance. Higher-rate landlords are worse off, because they now get 20% relief on interest instead of 40%.
Can I use the £1,000 property allowance instead of expenses?
Yes, if it leaves you paying less tax. You either deduct the flat £1,000 property allowance from your gross rents or claim your actual allowable expenses, never both. The allowance suits landlords with very low costs. If your real expenses exceed £1,000, as most letting costs do, claim the actual figures instead.
Do I pay National Insurance on rental income?
No. Ordinary rental income is investment income, not trade, so it carries no Class 2 or Class 4 National Insurance, only Income Tax on the profit. The exception is running property as a genuine business with significant services, such as a guest house, where National Insurance can apply.
How do landlords split rental income on a jointly owned property?
A married couple or civil partners who own a property jointly are taxed 50/50 by default, regardless of their actual shares, unless they file a Form 17 declaration reflecting the true ownership split. Unmarried joint owners are taxed on their actual beneficial share of the income.
When is the deadline to file a landlord tax return for 2025/26?
The online filing and payment deadline for the 2025/26 landlord tax return is 31 January 2027, with a paper deadline of 31 October 2026. New landlords must register for Self Assessment by 5 October 2026. A second payment on account, where due, follows on 31 July 2027.
Sources
- Renting out a property: paying tax and National Insurance, GOV.UK
- Tax relief for residential landlords: how it is worked out, GOV.UK
- Tax-free allowances on property and trading income, GOV.UK
- Self Assessment: UK property (SA105), GOV.UK
- Understand your Self Assessment tax bill: payments on account, GOV.UK
