Self Assessment Tax Return: Property Income, SA105, and Deadlines

If you rent out property in the UK, you file a Self Assessment tax return for your rental income once your gross rents exceed £10,000 in a tax year, or once your profit after expenses exceeds £2,500.¹ You report the figures on the SA105 supplementary pages, which attach to your main SA100 return. The UK tax year runs from 6 April to 5 April, and your rental profit gets added to your other income and taxed at your marginal rate.²

When You Have to File

The first £1,000 of property income each tax year is covered by the property allowance, so if your gross rents stay under £1,000 you have nothing to report.¹ Between £1,000 and the main filing thresholds, contact HMRC directly: they can often collect the tax by adjusting your PAYE code instead of asking for a full return.

A Self Assessment return becomes compulsory once gross property income reaches £10,000 (whatever your expenses are) or once net profit exceeds £2,500. If you have never filed before, you must register for Self Assessment by 5 October following the end of the tax year in which you first received rental income.³ Missing that date does not remove the obligation. It just starts the penalty clock earlier.

Working Out Your Rental Profit

Your taxable profit is total rent from all your UK properties minus your allowable expenses. HMRC treats your non-holiday lettings as a single property business, so a loss on one automatically offsets a profit on another.⁴ Keep dated records for every transaction: rent books, bank statements, invoices, receipts.

What You Can Deduct

Any cost incurred wholly and exclusively for renting out the property is allowable. The common categories are:¹

Letting agent and management fees
Repairs and maintenance (fixing a leaking roof, repainting, replacing a broken boiler with a like-for-like equivalent)
Buildings, contents, and landlord liability insurance
Utility bills and council tax, where you pay them rather than the tenant
Legal and accountancy fees, including solicitor costs for tenancy agreements of a year or less
Advertising for new tenants
Ground rent and service charges on leasehold properties

What Counts as Capital

Anything that improves the property beyond its original condition is capital expenditure and cannot come off your rental income. Extensions, first-time installation of a security system, or replacing a kitchen with a significantly upgraded version all fall here.⁴ Keep the receipts anyway. Capital costs reduce your Capital Gains Tax bill if you sell later, so store them separately from routine maintenance so you do not accidentally claim them in the wrong place.

Replacing Furniture and Appliances

When you replace a furnishing or appliance in a residential let, you can usually deduct the replacement cost. This covers furniture, curtains, carpets, appliances such as fridges and televisions, and kitchenware, and it applies to furnished, part-furnished, and unfurnished properties.⁴ Upgrades come with a limit: swap a plain sofa for a sofa bed and you can only claim what a like-for-like sofa would have cost. A reasonable modern equivalent, such as a more efficient fridge replacing an older one, counts as a straight replacement. You cannot claim this relief for the initial furnishing of a property, only for replacements.

Mortgage Interest: The Big Trap

This is where residential landlords go wrong more than anywhere else. Since the 2020/21 tax year, mortgage interest and other finance costs on residential lettings cannot be deducted from rental income. Instead, you get a basic-rate 20% tax credit against your final bill.⁵ The rule covers interest and incidental borrowing costs such as arrangement fees.⁶

A 40% taxpayer with £5,000 of mortgage interest gets a £1,000 credit rather than the £2,000 deduction the old system would have given. On the return, keep mortgage interest out of your general expenses figure. It goes in its own box on the SA105, and mixing it in with other costs leads to double-counting that HMRC’s systems flag.

The restriction is residential only. If you let commercial property, finance costs remain fully deductible.

The £1,000 Property Allowance

Instead of listing actual expenses, you can claim a flat £1,000 property allowance and ignore your real costs entirely. You cannot do both.⁷ For most landlords with mortgages, insurance, and maintenance to claim, actual expenses dwarf £1,000 and the allowance is not worth taking. It mainly helps people with tiny costs, such as someone renting out a driveway or a storage space. If you want to claim a loss and carry it forward, you must elect out of the allowance and use your real figures.

Joint Ownership With a Spouse or Partner

If you own a rental property jointly with a spouse or civil partner, HMRC assumes a 50/50 split of income and expenses, regardless of who put in the deposit or manages the tenants.⁸ Each of you reports your half on your own return.

You can change the split only if you hold the property as tenants in common with unequal shares. You submit Form 17 to HMRC with evidence of the actual shares, such as a deed or declaration of trust. Joint tenants (who each own the whole property equally) cannot override the 50/50 default without first changing the ownership structure, which needs legal advice.

Filling In the SA105

The SA105 supplementary pages are where UK rental income goes.⁹ You can file online through HMRC’s portal or download a paper version. The form runs in a logical order: income, then expenses, then finance costs.

The “total rents and other income from property” box takes your gross figure before any deductions.¹⁰ Separate expense boxes cover professional fees, repairs, insurance, and other running costs. Enter revenue expenses only, never capital improvements.

Residential mortgage interest belongs in the dedicated “Residential property finance costs” box, where the 20% tax credit is calculated. Do not put it in the general expenses section as well. Non-residential finance costs, if you also let commercial property, have their own separate box.

If You Make a Loss

When allowable expenses exceed rental income, you make a loss. You carry it forward against future profits from the same property business. You cannot use a rental loss to reduce employment income or other non-property earnings.¹

Letting at below-market rent (to a family member, for instance) restricts your expenses on that property to the amount of rent received, so no loss can arise from it. The excess expenses are lost and cannot be used later, even once you start charging full rent. If your rental business ends entirely, carried-forward losses generally disappear unless you restart within three years with the same property.

Non-Resident Landlords

If your usual home is outside the UK but you own UK rental property, the Non-Resident Landlords Scheme applies regardless of the rent amount. Your letting agent, or the tenant if there is no agent, must withhold tax from your rent each quarter and pay it to HMRC.¹¹ To receive rent without deduction, individuals apply on form NRL1. Approval means you are registered for Self Assessment and directly responsible for reporting and paying the tax yourself.

Deadlines, Penalties, and Payments on Account

Paper returns must reach HMRC by midnight on 31 October following the end of the tax year. Online returns are due by midnight on 31 January.² For the 2025/26 tax year, that makes the online deadline 31 January 2027. Your tax bill is due on the same 31 January date. Interest runs on anything paid late.

Late filing brings an automatic £100 penalty even if you owe nothing. After three months, daily penalties of £10 kick in, up to £900. At six months, a further penalty of 5% of tax due or £300 (whichever is greater) applies, and the same again at twelve months.¹² A return a full year late can attract over £1,600 in penalties before the tax itself.

Errors on the return carry their own penalties, calculated as a percentage of the extra tax owed and reduced when the taxpayer discloses voluntarily and cooperates.¹³

If last year’s Self Assessment bill was £1,000 or more, HMRC usually asks for payments on account: two equal instalments toward next year’s tax, each half of the previous year’s bill, due 31 January and 31 July.¹⁴ You are exempt if more than 80% of your tax was collected at source, for example through PAYE. In your first profitable year, this stings: on the same 31 January, you pay the tax for that year plus the first instalment on next year’s, roughly 150% of one year’s tax in one go. Budget for it from the start.

Furnished Holiday Lettings Regime Ended

The special tax regime for furnished holiday lettings ended on 5 April 2025. Holiday lets are now taxed as ordinary rental income. Mortgage interest falls under the same 20% credit restriction as other residential lettings. Capital allowances on new furniture and equipment are no longer available, though Replacement of Domestic Items Relief still applies to replacements of existing items.

On sale, holiday lets no longer qualify for Business Asset Disposal Relief (previously a 10% Capital Gains Tax rate on up to £1 million of gains) or rollover relief; sales attract standard residential Capital Gains Tax rates. Holiday let profits no longer count as relevant UK earnings for pension contributions, and losses can only be carried forward against future property income. The SA105 form no longer contains separate furnished holiday lettings sections. If you ran a holiday let before April 2025, these changes bite from the 2025/26 tax year.

Making Tax Digital From April 2026

How rental income is reported changes materially in April 2026. Making Tax Digital for Income Tax requires landlords over the relevant income threshold to keep digital records with compatible software and send quarterly updates to HMRC, in addition to a year-end final declaration. The rollout is phased:¹⁵

From 6 April 2026: landlords and self-employed individuals with qualifying income over £50,000 in the 2024/25 tax year
From 6 April 2027: those with qualifying income over £30,000 in the 2025/26 tax year
From 6 April 2028: those with qualifying income over £20,000 in the 2026/27 tax year

Qualifying income combines gross rental income and self-employment income. If you are over the threshold, you will need MTD-compatible software, or bridging software that links a spreadsheet to HMRC’s systems. Below the active threshold for your year, ordinary Self Assessment filing continues. The direction is set, though, and moving to digital record-keeping now saves a scramble later.

1
GOV.UK. Renting Out Your Property: Paying Tax and National Insurance
2
GOV.UK. Self Assessment Tax Returns: Deadlines
3
GOV.UK. Check How to Register for Self Assessment
4
GOV.UK. Work Out Your Rental Income When You Let Property
5
legislation.gov.uk. Finance (No. 2) Act 2015 – Section 24
6
HMRC. Property Income Manual – PIM2054
7
GOV.UK. Tax-Free Allowances on Property and Trading Income
8
GOV.UK. Declare Beneficial Interests in Joint Property and Income
9
GOV.UK. Self Assessment: UK Property (SA105)
10
HM Revenue & Customs. SA105 – UK Property
11
GOV.UK. What the Non-Resident Landlords Scheme Is
12
GOV.UK. Self Assessment Tax Returns: Penalties
13
GOV.UK. Penalties: An Overview for Agents and Advisers
14
GOV.UK. Understand Your Self Assessment Tax Bill: Payments on Account
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GOV.UK. Find Out If and When You Need to Use Making Tax Digital for Income Tax