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How to fill in the UK property pages (SA105) for 2025-26

Tax year 6 April 2025 to 5 April 2026. Checked against HMRC's 2025-26 form and notes, October 2026.

If you let out a house, flat or room (and it isn't your own home), you report the rent on the "UK property" pages. Here's what each box means, how jointly owned lets work, and how to choose between the £1,000 allowance and your actual costs.

On this page
  1. Do you need to fill them in?
  2. Jointly owned property
  3. £1,000 allowance or actual costs?
  4. Box by box
  5. Worked example
  6. Mortgage interest

Do you need to fill them in?

The £1,000, £2,500 and other limits are all based on your share of the rent before costs.

Jointly owned property

If you own and let a property with someone else, each of you reports only your own share of the rent and costs on your own return. Put an X in box 3.

£1,000 allowance or actual costs?

You can either take £1,000 off your rent (box 20.1) or deduct your real letting costs. You can't do both.

You can choose again each year.

Box by box

These are HMRC's box numbers for 2025-26. The online return asks the same questions. Boxes 5 to 19 are no longer used, because the furnished holiday lettings rules ended in April 2025.

BoxWhat it asksWhat to enter
1Number of properties rented outHow many you let.
3Income from property let jointlyX if jointly owned. Then use your share everywhere below.
20Total rents and other income from propertyAll rent due for the year (your share), before any costs or agent fees.
20.1Property income allowance£1,000, or the rent if it's less. Only if you're not claiming costs.
20.2Traditional accountingLeave blank unless you use accruals instead of the cash basis. Most small landlords use the cash basis.
24Rent, rates, insurance and ground rentsLandlord insurance, ground rent and service charges, and any council tax you paid between tenants.
25Property repairs and maintenanceRepairs and redecorating to keep the property as it was. Not improvements.
26Non-residential property finance costsOnly for commercial lets. Residential mortgage interest goes in box 44.
27Legal, management and other professional feesLetting agent fees, accountant fees, legal fees for lets of a year or less.
28Costs of services providedCleaning, gardening, and bills you pay for the tenant.
29Other allowable property expensesGas safety certificates, advertising, phone calls, travel to the property.
36Costs of replacing domestic itemsLike-for-like replacement furniture, appliances, carpets and curtains. Not the first purchase.
38Adjusted profit for the yearBox 20 minus box 20.1, or minus your costs (boxes 24 to 29 and 36).
39Loss brought forward used this yearFrom box 43 of last year's return, up to the box 38 figure.
40Taxable profit for the yearBox 38 minus box 39.
41Adjusted loss for the yearIf your costs were more than the rent.
43Loss to carry forwardThis year's loss plus any unused losses from earlier years.
44Residential property finance costsMortgage interest (your share) on a residential let. Not capital repayments.
45Unused residential finance costs brought forwardInterest you couldn't get relief on in earlier years.

Worked example

Sam and Alex, a married couple, jointly own a flat let for £12,000 a year. Their costs for the year were insurance £400, repairs £1,500 and agent fees £700, plus £3,000 mortgage interest. Each reports half. Sam is a basic-rate taxpayer.

Sam's returnOption A: allowanceOption B: actual costs
Box 3XX
Box 20 rent (half)£6,000£6,000
Box 20.1 allowance£1,000-
Box 24 insurance-£200
Box 25 repairs-£750
Box 27 agent fees-£350
Box 38 and 40 profit£5,000£4,700
Box 44 mortgage interest-£1,500
Tax at 20% on the profit£1,000£940
Less 20% of mortgage interest--£300
Extra tax for the year£1,000£640

Claiming actual costs saves Sam £360. Alex fills in the same figures on their own return.

Mortgage interest on a residential let

Since April 2020 you can't deduct mortgage interest from residential rent. Instead you put it in box 44, and HMRC takes 20% of it off your tax bill. This is basic-rate relief whatever rate you pay. The reduction is limited to 20% of the lowest of:

If profits limit the relief, the unused interest carries forward to next year.

Want your exact figures? The calculator asks about your rent and costs, works out your share, tries the allowance and actual costs both ways, and gives you every box to copy in.

Work out my figures - free

Sources

General guidance, not tax advice. For unusual situations (Rent a Room, overseas property, a lease premium) read the HMRC notes or ask an accountant.