SA105 Property Pages Box by Box
Box 20 income, Boxes 24–29 expenses, Box 36 domestic items, Box 44 mortgage interest — the trap. Verified against HMRC's notes, with the £1,000 allowance decision and deadlines.
The short answer
The SA105 is the ‘UK property’ page of your tax return. Income goes in Box 20, running costs in Boxes 24–29, replaced furniture in Box 36 — and residential mortgage interest goes in Box 44, never in the expenses boxes. That one misplacement is the most common landlord error HMRC corrects. Box numbers verified against HMRC’s SA105 notes.
If you are not yet inside Making Tax Digital — most landlords under £50,000 gross are not — the SA105 is still how your rental profit is reported. Here is every box that matters, in order, and what goes in it.
Income
| Box | What goes in |
|---|---|
| Box 20 — Total rents and other income from property | Gross rent received (cash basis) or due (accruals) from all UK properties, before agent fees. Include service charges you collect. |
| Box 21 — Property income allowance | Enter £1,000 here only if you are claiming the allowance instead of expenses (see below). |
| Box 22 — Premiums for the grant of a lease | Rare for residential ASTs. |
| Box 23 — Reverse premiums | Rare. |
Expenses (Boxes 24–29)
| Box | What goes in |
|---|---|
| Box 24 — Rent, rates, insurance, ground rents | Ground rent, service charges, council tax and utilities you pay (including during voids), landlord insurance. |
| Box 25 — Property repairs and maintenance | Revenue repairs: like-for-like boiler, decorating, same-footprint kitchen. Not improvements. |
| Box 26 — Non-residential property finance costs | Interest on commercial lets only. Not buy-to-let mortgage interest. |
| Box 27 — Legal, management and other professional fees | Agent fees, accountancy, tenancy legal costs. |
| Box 28 — Costs of services provided, including wages | Cleaning, gardening or other services you provide to tenants. |
| Box 29 — Other allowable property expenses | Safety certificates, licence fees, mileage, phone, software, advertising. |
Adjustments and reliefs
| Box | What goes in |
|---|---|
| Box 30 — Private use adjustment | Add back the private share of any expense with mixed use (e.g. a property you also use). |
| Box 31 — Balancing charges | Rare for residential. |
| Boxes 32–35 — Capital allowances | Rarely available for dwellings; leave blank unless advised. |
| Box 36 — Costs of replacing domestic items | Replacement of domestic items relief — furniture, white goods, kitchenware you replaced. |
| Box 37 — Rent a Room exempt amount | Only if you let a room in your own home under the £7,500 scheme and are using the alternative method. |
| Box 38 — Adjusted profit / Box 41 — loss | Income minus Boxes 24–29 and 36, plus Box 30. |
| Box 39/43 — Losses brought forward and used | Property losses from earlier years, against this year’s profit. |
The finance-cost boxes
| Box | What goes in |
|---|---|
| Box 44 — Residential property finance costs | Buy-to-let mortgage interest, arrangement and broker fees, early repayment charges. HMRC applies the 20% Section 24 credit from this box — it is not deducted from profit. |
| Box 45 — Unused residential finance costs brought forward | Where last year’s credit was capped, the excess carried forward goes here. |
The Box 44 trap in numbers
A higher-rate landlord with £12,000 profit before interest and £6,000 of mortgage interest who wrongly puts the interest in Box 26 pays tax on £6,000 (£2,400). Correctly, they pay tax on £12,000 (£4,800) less a 20% credit of £1,200 = £3,600. The wrong entry under-declares by £1,200 — and HMRC’s systems flag Box 26 entries on residential lets.
Expenses or the £1,000 allowance?
If your allowable expenses are under £1,000, claim the property income allowance instead (Box 21) — but then you claim no expenses and no finance costs at all. With any mortgage, actual expenses almost always win.
Deadlines
Paper returns by 31 October; online by 31 January after the tax year; tax due 31 January. New landlords must register for self assessment by 5 October following the first tax year with property income. If you are mandated into MTD, the quarterly updates and final declaration replace the SA105 for that year — see the first-update walkthrough.
HMRC SA105 notes (2025 edition PDF, box titles verified 31 Aug 2026: Boxes 20, 24–29, 36, 44, 45); gov.uk self-assessment deadlines; Section 24 rate from our verified 2026/27 dataset.
Quick answers
Box 44 — residential property finance costs. Not Boxes 24–29. HMRC gives a 20% tax reduction on Box 44; putting interest in the expenses boxes wrongly deducts it in full.
If your gross property income is £1,000 or less it is covered by the property allowance and need not be reported. Above that, complete the SA105 (you can still choose the allowance instead of expenses).
Box 27 — legal, management and other professional fees.
For landlords mandated into MTD for Income Tax, quarterly updates plus the final declaration replace the SA105 for that year. Everyone else keeps using it.