Landlord Tax Return Checklist 2025/26 (Before 31 Jan 2027)
Every SA105 box, the £1,000 allowance vs expenses choice, rent-a-room, Form 17 and payments on account, before the 31 January 2027 deadline.
The short answer
The 2025/26 Self Assessment return — due online by 31 January 2027 — is a normal SA105 return for every landlord, whatever your income. Making Tax Digital doesn't touch this particular year even for the first wave of landlords mandated into it: their obligation starts from 6 April 2026, which falls in the following tax year. This checklist works through the SA105 boxes for 2025/26 box by box, the £1,000 property allowance versus claiming actual expenses, rent-a-room, jointly owned property and Form 17, and the payments that actually fall due on 31 January 2027. SA105 and its box numbers are the same UK-wide — income tax is a reserved matter HMRC administers everywhere, so this checklist applies whether you pay rest-of-UK, Scottish or Welsh income tax rates; only the rate bands differ.
The date that matters: 31 January 2027
HMRC's own UK property notes for 2025/26 are explicit: even if you decide you don't need to file at all, “you must tell us by 31 January 2027 to avoid paying penalties.” If you do file, the same date covers your online return, your 2025/26 balancing payment, and your first payment on account for 2026/27 if one applies — three things on one bill, the usual source of a January surprise. Registering for Self Assessment for the first time has its own earlier deadline (5 October); see this site's Self Assessment deadlines guide if that applies to you.
SA105 boxes, box by box
Every landlord filing the traditional way uses the same core boxes, verified here against HMRC's UK property notes for the return due 31 January 2027:
| SA105 box | What goes in it (2025/26) |
|---|---|
| Box 20 — Total rents and other income | Gross rent and related income (ground rents, service charges you collect) before agent fees. Cash basis is available up to £150,000 of total property income. |
| Box 20.1 — Property income allowance | Claim the £1,000 allowance here instead of expenses — see the trade-off below. Leave blank if you're claiming actual expenses. |
| Box 24 — Rent, rates, insurance, ground rents | Ground rent, council tax and utilities during voids, landlord insurance, business/water rates you pay. |
| Box 25 — Repairs and maintenance | Like-for-like repairs — painting, damp treatment, a replacement boiler. Not improvements. |
| Box 26 — Non-residential finance costs | Loan interest on commercial lets only — never residential buy-to-let mortgage interest. |
| Box 27 — Legal, management and professional fees | Letting agent fees, accountancy, eviction costs for re-letting, appealing a compulsory purchase order. |
| Box 28 — Cost of services provided, including wages | Cleaning, gardening or other services you provide to tenants (offset by any income you charge for them). |
| Box 29 — Other allowable expenses | Phone, stationery, travel, mileage. If total income before expenses is under £90,000, HMRC lets you total everything here without splitting boxes 24-28. |
| Box 36 — Replacing domestic items | Furniture, white goods, carpets and kitchenware you replaced for tenants — not the very first fit-out. |
| Box 37 — Rent-a-room exempt amount | Only if you let a room in your own home and are using the £7,500 (£3,750 if let jointly) alternative method. |
| Boxes 38/41 — Adjusted profit / loss | Income plus balancing charges, minus boxes 24-29, 36 and any rent-a-room or property-allowance amount. |
| Boxes 39/42/43 — Losses | Brought-forward losses used against this year's profit, any set against total income (capital allowances/agricultural only), and the balance carried forward. |
| Box 44 — Residential property finance costs | Buy-to-let mortgage interest, arrangement and broker fees. Generates a 20% tax reduction — it is not deducted from profit. |
| Box 45 — Unused residential finance costs b/f | Any of last year's Box 44 credit that was capped and carried forward. |
The £1,000 property allowance vs claiming expenses
This is a binary choice, not a top-up. Gov.uk's guidance is explicit: claim the £1,000 allowance and you cannot also deduct expenses or claim the residential finance-costs reduction (Box 44) — the two are mutually exclusive. If your genuine running costs are worth less than £1,000 a year, the allowance is simpler. With a mortgage and real running costs, itemising almost always wins once the 20% finance-cost credit is added in — see this site's allowable expenses guide for the full list.
Renting a room, not a whole property
Letting a furnished room in your own home uses a different limit — Rent a Room's £7,500 (£3,750 if shared) — see this site's Rent a Room Scheme guide for the two methods above that limit and which saves more.
Jointly owned property and Form 17
HMRC's default for spouses and civil partners living together is a strict 50/50 split, regardless of your actual ownership share. To follow a different split you need Form 17 — “Declaration of beneficial interests in joint property and income” — covered in detail, including the 60-day filing window, on this site's joint ownership & Form 17 guide. Non-spouse co-owners are taxed on their actual agreed share from the outset, with no Form 17 needed.
Payments on account
Your 31 January 2027 bill isn't necessarily just the balancing payment. If your Self Assessment bill was £1,000 or more, with under 80 per cent of your tax collected at source, HMRC adds two payments on account towards 2026/27 — each half of your 2025/26 bill, due 31 January and 31 July. Expect a lower profit next year? Form SA303 reduces them in advance; this site's payments on account calculator works out both together.
Making Tax Digital: why it doesn't touch this return
Easy to assume MTD already applies if you've heard the £50,000 headline — it doesn't, for this return. Even the first MTD wave (gross qualifying income over £50,000 in 2024/25) is mandated only from 6 April 2026, the start of 2026/27. Every landlord files 2025/26 the traditional way on SA105; if you're mandated from April 2026, your next submission switches to quarterly updates — use this site's MTD checker to confirm your date.
Printable checklist
- Gather total rent received and any other property income (Box 20 figure).
- Decide: £1,000 property allowance, or actual expenses plus the Box 44 finance-cost credit — not both.
- If itemising, sort receipts into Boxes 24-29 (or one Box 29 total if income is under £90,000).
- Add up mortgage interest and finance fees separately for Box 44 — keep it out of Boxes 24-29 entirely.
- Check for domestic-item replacements (Box 36) and any brought-forward losses (Box 39/43).
- If jointly owned with a spouse/civil partner and your real split isn't 50/50, confirm Form 17 has been filed for this property.
- Work out whether payments on account apply for 2026/27, and whether to reduce them on Form SA303.
- File and pay by 31 January 2027 — earlier if you want time to fix errors before the deadline.
None of this is tax advice — it's a plain-English map of HMRC's own rules for 2025/26. An accountant is the right call for anything unusual: a part-year let, a mid-year sale, or a loss to carry back.
gov.uk/self-assessment-uk-property-sa105 (2025/26 UK property form and notes, last updated 6 April 2026) · HMRC UK property notes for 2025/26 (box-by-box rules, the £90,000 and £150,000 thresholds, the 31 January 2027 deadline, quoted verbatim, checked 13 Sep 2026) · gov.uk/guidance/tax-free-allowances-on-property-and-trading-income (property allowance vs finance-cost relief, mutually exclusive, checked 13 Sep 2026) · property allowance, rent-a-room, payments-on-account and Section 24 figures from this site's own site/taxdata.py (verified 29 Aug 2026); MTD wave-1 threshold and date from the same file (gov.uk find-out-if-and-when, updated 26 Mar 2026). General information, not advice.
Quick answers
Box 20 — your total UK rents and other property income for the year, gross before letting agent fees, per HMRC's UK property notes for 2025/26. Premiums for granting a lease and reverse premiums have their own boxes, 22 and 23.
No. Gov.uk's own guidance on property allowances is explicit that the two are mutually exclusive: claim the £1,000 allowance and you cannot also deduct expenses or claim the residential finance-costs tax reduction (Box 44) on the same property income.
31 January 2027 — for the online return, the balancing payment, and, per HMRC's own SA105 notes, for telling HMRC if you've decided you don't need to file at all. It's also when your first payment on account for 2026/27 falls due, alongside the 2025/26 balancing payment.
Only if you want a split other than the default 50/50 HMRC applies to spouses and civil partners living together. Form 17, "Declaration of beneficial interests in joint property and income," must be filed within 60 days of the underlying declaration of trust to change that default.
No, not for anyone. Even the first MTD wave (gross qualifying income over £50,000 in 2024/25) is mandated only from 6 April 2026, which falls in the following tax year — so 2025/26 is filed the traditional way on SA105 regardless of income.