SA105 2026: The Landlord Tax Return, Box by Box

If you let property in the UK, the heart of your tax return is the SA105 UK property pages. For the 2025/26 tax year (the year ended 5 April 2026) these are the supplementary pages where you declare rental income, claim allowable expenses, apply the Section 24 finance-cost rules, and arrive at the property profit that feeds your overall Self Assessment. This guide walks through the SA105 box by box, sets out the SA105 Notes you should be reading alongside it, and covers the deadlines and penalties, allowable expenses with a full Section 24 worked example, Capital Gains Tax on a sale, the SA109 for non-residents, and how Making Tax Digital changes the routine from April 2026.

Two things have shifted since older guides were written, and both matter for 2025/26. The furnished holiday lettings regime has been abolished, so there is no separate holiday-let treatment any more. And Making Tax Digital for Income Tax is now live for the largest landlords, with the first £50,000 threshold biting from 6 April 2026. Both are flagged in context below.

What is the SA105 and which forms do landlords need?

Self Assessment for landlords is built from the main return plus the property supplement. The SA105 is not a standalone form you post on its own; it is a set of pages that sit inside your return.

• SA100 is the main Self Assessment return that everyone completes.
• SA105 is the UK property supplement. You complete one set of SA105 pages covering all your UK rental income. You do not file a separate SA105 for each property; you aggregate the figures across your whole UK property business.
• SA106 is the foreign pages, used for overseas rental property and other foreign income.
• SA108 is the Capital Gains Tax summary, used in the year you sell a property at a gain (separate from the in-year 60-day reporting described later).
• SA109 is the residence and remittance pages, relevant to non-UK residents and to anyone arriving in or leaving the UK part-way through the year.

Online filers complete the SA105 inside HMRC's Self Assessment service or commercial software, so there is no separate paper form to chase. Paper filers, and anyone who wants the box-by-box reference, can download the SA105 form and the SA105 Notes for the year on gov.uk. The Notes are the authoritative guidance that explains every box, and HMRC reissues them annually. Box numbers occasionally shift between years, so when you read any guide, including this one, cross-check the box references against the SA105 Notes for the exact year you are filing. The walkthrough below uses the 2025/26 layout.

The SA105 box by box for 2025/26

The SA105 property pages are where your rental figures land. The table below maps the entries that catch most landlords out. Box 44 is the one to understand: that figure is not deducted from profit, it drives your basic-rate Section 24 tax reducer instead.

Box	What goes in it	Common mistake
Box 20	Total rents and other income from your UK property business for the year	Reporting rent net of agent commission instead of gross
Box 20.1	Property allowance claimed (£1,000) in place of actual expenses	Claiming the allowance and actual expenses against the same income
Box 22	Tax already deducted at source, for example under the Non-Resident Landlord scheme	Forgetting to claim credit for tax a letting agent has withheld
Boxes 24 to 29	Allowable expenses by category (agent fees, repairs, insurance, professional fees, other costs)	Putting mortgage interest here rather than in box 44
Box 44	Residential finance costs (mortgage interest) for the Section 24 reducer	Deducting the figure from profit instead of letting it drive the 20% reducer

Your adjusted profit is income less the box 24 to 29 expenses, with finance costs handled separately through the reducer and any brought-forward property losses set against the result. For a full walkthrough of every box and the common filing mistakes, see our dedicated reference, SA105 property income form 2026: every box explained.

Key deadlines and penalties

Missing a filing date triggers automatic penalties, so the timeline is worth pinning down early. For a fuller treatment see our guide to the landlord tax return deadline for 2026.

2025/26 Self Assessment dates

• 5 October 2026: deadline to register for Self Assessment if 2025/26 is your first year with rental income.
• 31 October 2026: deadline if you file a paper return by post.
• 31 January 2027: deadline to file online, and to pay any tax owed for 2025/26.
• 31 January 2027: first payment on account for 2026/27, if you are within the payments-on-account regime.
• 31 July 2027: second payment on account for 2026/27, if applicable.

Late filing penalties

• £100 fixed penalty the day after the deadline, even if no tax is due.
• Daily penalties of £10 a day (up to £900) once the return is three months late.
• Further tax-geared penalties at six and twelve months.
• Separate penalties and interest apply to tax paid late.

What counts as rental income

Report all income from the property business for the year, not just the headline rent:

• Rent received from tenants.
• Deposits you keep to cover damage, cleaning or unpaid rent.
• Insurance payouts that compensate for lost rent.
• Charges to tenants for services such as cleaning, gardening or utilities you arrange.
• Grants and incentive payments connected with the letting, including some reverse premiums.

Most unincorporated landlords use the cash basis, which is the default: you report rent when it is received and expenses when they are paid. You must use the accruals (GAAP) basis instead if your cash receipts for the year exceed £150,000, or you can elect into accruals voluntarily (ITTOIA 2005 section 271A). Under the cash basis, December 2025 rent that a tenant actually pays in January 2026 falls into the 2025/26 tax year, because that is when you received it.

Allowable expenses and deductions

You can deduct costs incurred wholly and exclusively for the rental business. Getting this right is the difference between a fair tax bill and an inflated one, and the most common HMRC enquiries into landlords start with expense errors.

Fully deductible expenses

• Letting agent and property management fees.
• Buildings and contents insurance.
• Ground rent, service charges and rents you pay out.
• Repairs and maintenance (see the repairs-versus-improvements distinction below).
• Accountancy, legal and other professional fees relating to the letting.
• Advertising for tenants and tenant referencing or credit checks.
• Utilities and council tax you pay (for example during void periods or where bills are not recharged).
• The running cost of visits to the property for management purposes.

The £1,000 property allowance

The property allowance (ITTOIA 2005 Part 6A) gives a £1,000 deduction in place of actual expenses, claimed in box 20.1. If your gross rents are £1,000 or less, the allowance usually means you have nothing to report. If your rents are higher, you choose each year between deducting the £1,000 allowance or your actual expenses, whichever leaves the lower taxable profit. You cannot use both against the same income, and the allowance is per person, not per property.

Repairs versus improvements

A repair restores the property to its previous condition and is deductible: replacing a failed boiler with a similar model, repainting between tenancies, or fixing guttering. An improvement goes beyond the original and is capital expenditure, not deductible against rental profit: an extension, or fitting a substantially superior kitchen where there was a basic one. A like-for-like replacement is still a repair even if the modern equivalent is a modest upgrade on the old item. Capital improvement spending is usually added to the property's base cost and reduces the Capital Gains Tax bill when you sell.

The Section 24 finance-cost restriction

Since 6 April 2020 individual residential landlords cannot deduct mortgage interest and other finance costs from rental profit. Instead, the finance costs go in box 44 and HMRC gives a basic-rate tax reducer against your overall income tax. The reducer is 20% of the lowest of three figures: the finance costs for the year, the residential property profit, and your adjusted total income above the personal allowance (ITTOIA 2005 sections 272A and 274A). Any finance cost not relieved because of the cap carries forward indefinitely. This is the rule that pushes leveraged higher-rate landlords into a higher effective tax position, and it is set out in detail in our Section 24 mortgage interest restriction guide and the practical mechanics in how to claim mortgage interest relief under Section 24.

Looking ahead. The reducer is not frozen at 20%. From 2027/28, Finance Act 2026 (which received Royal Assent on 18 March 2026) introduces separate property income rates of 22%, 42% and 47% for England, Wales and Northern Ireland, with only Scotland carved out, and gives the Section 24 reducer at the new 22% property basic rate. Because the reducer rises in step with the basic rate, a basic-rate landlord sees no new wedge from this change. A higher-rate landlord's relief rises from 20% to 22%, but still sits well below their 42% marginal rate, so the restriction continues to bite hardest on heavily mortgaged higher-rate portfolios.

Section 24 worked example

Numbers make Section 24 concrete. Take a higher-rate-taxpayer landlord with a single buy-to-let. The 2025/26 figures are rental income of £18,000, allowable expenses (agent fees, insurance, repairs) of £3,000, and mortgage interest of £9,000. Under the current rules the calculation runs like this.

Step	Amount
Rental income (box 20)	£18,000
Less allowable expenses (boxes 24 to 29)	(£3,000)
Taxable rental profit (mortgage interest not deducted)	£15,000
Income tax on £15,000 at the 40% marginal rate	£6,000
Less Section 24 reducer: 20% of £9,000 interest (box 44)	(£1,800)
Net income tax on the rental profit	£4,200

Before Section 24, this landlord would have deducted the full £9,000 interest, leaving a £6,000 profit taxed at 40%, so £2,400. Under the restriction the bill is £4,200, which is £1,800 more on the same economic position. The reducer is capped at 20% of the lowest of the interest (£9,000), the property profit (£15,000), and income above the personal allowance, so here the full £1,800 is given. The wider the gap between the interest bill and the profit, the more the cap can bite, which is why heavily mortgaged higher-rate landlords feel Section 24 most. Several respond by reviewing whether a limited company structure, where interest remains fully deductible, suits their portfolio.

Capital allowances: narrower than landlords expect

Capital allowances on plant and machinery are not available for items inside a residential dwelling let on an ordinary tenancy. You cannot claim the Annual Investment Allowance on a new cooker, carpets or furniture in a standard buy-to-let. Instead, the cost of replacing furnishings, appliances and similar movable items in a residential let is dealt with through replacement of domestic items relief, which gives a deduction for the cost of replacing (not initially providing) such items, restricted to a like-for-like standard.

Capital allowances do still apply in specific situations:

• Plant and machinery in the communal areas of a residential block (for example a lift or shared boiler) can qualify.
• Commercial lettings can claim capital allowances on qualifying fixtures and plant in the normal way.
• Capital allowances pooled before 6 April 2025 on a former furnished holiday let continue to receive writing-down allowances within the ongoing property business, even though the FHL regime has gone.

The end of the furnished holiday lettings regime

The furnished holiday lettings (FHL) regime was abolished from 6 April 2025. For 2025/26 there is no separate holiday-let category on the return: a former holiday let is reported on the SA105 as an ordinary residential let. In practice that means the Section 24 finance-cost restriction now applies to it, the old FHL capital allowances and Business Asset Disposal Relief routes are no longer available, and the profits no longer count as relevant earnings for pension contributions. Two transitional points survive: capital allowances already pooled before abolition keep their writing-down allowances, and unused FHL losses carry forward against the continuing property business. If you previously filed holiday-let pages, do not carry that treatment into your 2025/26 return.

Non-resident landlords, the SA109 and UK property pages

If you live abroad but let UK property, you still pay UK tax on that rental income and report it on the SA105 UK property pages, the same pages a UK-resident landlord uses. The SA109 residence pages confirm your residence status, and the Non-Resident Landlord (NRL) scheme may require your letting agent or tenant to deduct basic-rate tax from the rent before paying you, unless HMRC has approved you to receive rents gross (using forms NRL1, NRL2 or NRL3). Any tax withheld is entered in box 22 of the SA105 and credited against your liability.

A common question is whether the SA109 takes you out of digital filing. It does not. Making Tax Digital still applies to non-resident landlords wherever the qualifying income threshold is met, so the NRL scheme, the SA109 residence pages and MTD operate side by side rather than as alternatives. An overseas landlord above the threshold keeps digital records and files quarterly updates plus a final declaration in the same way a UK-resident landlord does.

Capital Gains Tax when you sell

The annual return covers rental income, but a sale brings Capital Gains Tax into play. For 2025/26 a gain on a residential investment property is taxed at 18% within your remaining basic-rate band and 24% above it (TCGA 1992 section 1H), after the £3,000 annual exempt amount. Where Capital Gains Tax is due, UK residents must file a CGT-on-UK-property return and pay the estimated tax within 60 days of completion, which is a separate filing from the annual Self Assessment. The gain is then also reported on the SA108 pages of that year's return, with the 60-day payment credited. Non-UK residents must file the 60-day return for every UK property disposal, whether or not tax is due. The full picture, including the current rates and reliefs, is in our CGT rates on property guide and the complete Capital Gains Tax guide for landlords.

Record-keeping for the return and for MTD

Good records make the SA105 straightforward and protect you if HMRC opens an enquiry. Keep:

• Rent statements and bank records showing income received.
• Receipts and invoices for every expense you claim.
• Annual mortgage interest certificates, which feed box 44.
• Letting agent statements showing gross rent, commission and deductions.
• Purchase, legal and improvement paperwork, which you will need to calculate Capital Gains Tax years later when you sell.

A practical retention rule for landlords is to keep records for at least five years after the 31 January filing deadline. Under Making Tax Digital those records must be kept digitally, with bank-feed data, app-captured receipt images or accounting-software entries all acceptable; loose paper receipts must be digitised. Building that habit now makes the move to quarterly reporting far less disruptive.

Getting ready for Making Tax Digital

Making Tax Digital for Income Tax (MTD for ITSA) replaces the single annual SA105 return with digital records, quarterly updates and a year-end final declaration. The mandate is phased by qualifying income, which is gross rents plus gross self-employment turnover, measured before expenses:

• From 6 April 2026: mandatory where qualifying income is above £50,000.
• From 6 April 2027: threshold drops to £30,000.
• From 6 April 2028: threshold drops to £20,000.

Because the test is on gross income, a landlord with £55,000 of rent but only £10,000 of profit is in scope at the April 2026 mandate. Limited companies are outside MTD for ITSA entirely, and general partnerships are deferred to a date still to be confirmed. Joint owners test the threshold against their own share of the gross rents, not the property's total, so the way income is split (including any Form 17 election) affects who is mandated and when. Our MTD qualifying income gross-versus-net guide works through the threshold test in detail, and the April 2026 MTD deadline guide covers what you need in place.

In-scope landlords file quarterly updates using HMRC-recognised software (or a spreadsheet linked to bridging software), followed by a final declaration by 31 January after the tax year. The standard quarters run to 5 July, 5 October, 5 January and 5 April, with updates due by the 7th of the following month, although calendar-quarter end dates can be elected. Late submissions move to a points-based regime, with a £200 penalty once you reach the four-point threshold, and MTD late-payment interest is charged on an accelerated schedule from 6 April 2026.

Common mistakes that trigger enquiries

• Treating a capital improvement as a repair (or vice versa).
• Still deducting mortgage interest from profit instead of routing it through the box 44 Section 24 reducer.
• Reporting rent net of agent fees as gross income, which understates both income and expenses and can make a landlord wrongly conclude they are below the MTD threshold.
• Carrying forward old furnished holiday let treatment into a 2025/26 return.
• Mixing personal and rental costs, or claiming the full cost of an asset used partly privately.
• Forgetting to report retained deposits or insurance recoveries.
• Missing the separate 60-day CGT return on a sale.

When professional help pays off

Property taxation has become noticeably more involved: Section 24, the abolition of the FHL regime, 60-day CGT reporting and the arrival of Making Tax Digital all sit on top of the basic SA105. A specialist property accountant can make sure the return is right, that you are using the most efficient accounting basis and structure, and that you are MTD-ready ahead of your mandate date rather than scrambling at the deadline. For a wider view of what is changing this year, see our 2026 landlord tax changes guide.