Know what HMRC will ask you for — and why.

About your properties Boxes 1–4 and 20.2

HMRC starts with the basics: which properties you let, who owns them, and whether you share the income with anyone. Get this right and the rest falls into place.

• A list of every property you let, with addresses Boxes 1–2
  Include any property abroad, or one you hold through a partnership: HMRC reports those on different pages, but can still ask about them in an enquiry.
• Proof of who owns each property, if you own any jointly Box 3
  For example the Land Registry title. If you and a partner split the income unequally, HMRC will also want the form you filed to say so (called Form 17). If someone else keeps your property records, such as an agent or a family member, HMRC may ask who.
• If you rent out a room in your own home: how much rent you got Box 4 Rare
  Only if you let a room in the house you live in. The tax-free limit is £7,500 a year (£3,750 if the home is jointly owned).
• How you worked out your figures: from money in and out, or from invoices Box 20.2
  Most small landlords count money when it arrives and leaves (HMRC calls this 'cash basis'). If an accountant did your books, they will know. If your accounts run to a date other than 5 April, HMRC will want to see how you split them across the tax year.
• If you ran a furnished holiday let before 6 April 2025: its separate records FHL Rare
  Holiday lets had their own tax rules until April 2025. An enquiry can cover earlier years, so keep the booking records and accounts for those years.

Money coming in Boxes 20–23

HMRC checks that the rent you declared matches the rent you actually received. This is usually the easiest part to prove, because your bank statements do most of the work.

• Tenancy agreements for every tenant you have had Box 20
  Our free Tenancy Records tool can keep the dates and details of each tenancy in one place.
• A list of the rent due each month, for each property Box 20
  A simple rent schedule; your letting agent may already produce one.
• Letting agent statements, if you use an agent Box 20
• Complete bank statements for every account the rent went into Box 20
  Send whole statements, not just the pages showing rent. Leaving pages out looks as if you are hiding something, even when you are not, and it makes the enquiry take longer.
• Any other money you received from the property Box 20
  Such as an insurance payout, a council grant for repairs, money for any other use of the property or land (a wayleave, filming, sporting rights), or money from a tenant for something other than rent. A tenant’s deposit is not income while you hold it, but any part you keep at the end of a tenancy is.
• Any lump sum a tenant paid you to take on a lease Box 22 Rare
  Rare for ordinary lets. If nobody paid you a lump sum, tap ‘Not me’.
• Any payment you received as an incentive to take on a property Box 23 Rare
  Rare. Usually only in commercial lets. Most landlords can tap ‘Not me’.
• If you live abroad: tax already taken off your rent Box 21 Rare
  Only if you are a landlord living outside the UK and tax was deducted before you got the rent.

Money going out Boxes 20.1 and 24–29

This is where HMRC looks hardest, because it is where landlords most often cannot find the receipts. Every cost you claimed needs a bill, invoice or receipt behind it.

• If you claimed the £1,000 tax-free property allowance instead of your actual costs: a note that you did Box 20.1
  You can use the £1,000 allowance or claim your real expenses, not both. If you used the allowance, HMRC will check you did not also claim costs. If you claimed costs, tap ‘Not me’. Limited companies cannot use this allowance. It is also not available if any of your rent comes from a family member or business partner (a ‘connected person’).
• Bills for council tax, water, insurance and ground rent you paid Box 24
  Only the ones you paid, not your tenant. If you rent a property and sublet it, the rent you pay counts here too.
• Invoices and receipts for repairs and maintenance Box 25
  Fixing, painting, replacing a broken boiler. Not improvements, which are a different thing; see the next area.
• Loan interest on a shop, office or other non-residential property Box 26 Rare
  Only for commercial property. Mortgage interest on houses and flats goes under 'Mortgage interest' below.
• Letting agent fees, and any solicitor or accountant fees Box 27
• Bills for services you provided to tenants: cleaning, gardening, a cleaner's wages Box 28
• Small costs: stationery, phone calls, travel to the property Box 29
  Keep a simple note of dates and mileage for travel. If your rent before costs is under £90,000 a year, HMRC lets you put all your costs in one total on the return, but it will still want the receipts behind the total.

Special claims and adjustments Boxes 30–37

This area only matters if you made a particular claim, or if a property was not let all year. If none of it rings a bell, that is fine: tap ‘Not me’ and move on.

• Receipts for replacing worn-out items: sofa, fridge, carpets, curtains Box 36
  You can claim a like-for-like replacement, but not the first time you bought the item. If you bought something better, you can claim the cost of a like-for-like replacement, not the extra for the upgrade.
• Invoices for improvements, kept separate from repairs Capital
  An improvement is something that makes the property better or bigger, like an extension or a new kitchen where there was none. HMRC checks these were not claimed as repairs.
• If the property was empty or you used it yourself for part of the year: the dates Box 30
  So the costs can be split fairly between business use and your own use.
• If you sold equipment you had claimed for: what you sold and for how much Box 31 Rare
  Rare for residential landlords. Most can tap ‘Not me’.
• Receipts for equipment or buildings you claimed a special allowance on Boxes 32–35 (incl. 33.1, 33.2, 34.1) Rare
  Only if you claimed 'capital allowances', for example on a commercial building or an electric-car charge point. Most residential landlords do not. If you bought a property with fixtures such as a fitted kitchen or heating system and claimed on them, HMRC may also ask for the agreement with the seller about their value (a ‘section 198 election’).
• If you rent a room in your own home: the tax-free amount you claimed Box 37 Rare
  Rent a Room relief, currently £7,500 a year (£3,750 if you own the home jointly).

Losses from earlier years Boxes 39–43

If you made a loss in an earlier year and used it to reduce this year’s tax, HMRC will want to trace it back to where it came from. The profit or loss itself (boxes 38 and 41) is worked out from the other areas, so there is no separate document for it.

• Last year's tax return, showing any loss you carried forward Box 43
  The figure is in box 43 of last year's property pages.
• Paperwork for any loss you set against your other income Box 42 Rare
  Rare. Only allowed in special cases: where the loss came from capital allowances, or from farm land. Most landlords can tap ‘Not me’.

Mortgage interest Boxes 44–45

The interest on a buy-to-let mortgage is not taken off as a normal cost. Instead it reduces your tax bill in a set way. HMRC checks the interest figure against the lender's statement, so one document does most of the work here.

• The yearly mortgage statement for each property, showing the interest paid Box 44
  Your lender sends this every year, usually by post or in your online account. Our free Mortgage Records tool can keep the details of each loan in one place.
• The mortgage offer or loan agreement, and any fees you paid to set it up Box 44
• Last year's return, if you had interest you could not use Box 45
  Sometimes not all the interest can be used in one year and it is carried forward. If you are not sure, check box 45 of last year's return.

Your tax return and HMRC's letters The return under enquiry

Keep everything HMRC has sent you in one place, with the reference numbers, next to the return they are asking about. Knowing exactly what HMRC has asked for is half the battle.

• A copy of the tax return HMRC is asking about Forms SA100 and SA105
  SA100 is the main tax return; SA105 is its property pages. If you file online you can download both from your HMRC account.
• Every letter HMRC has sent you, with the reference numbers and dates
• Details of any other income HMRC has asked about
  For example a job, a pension or savings interest.
• If you share a property with someone: how the income is split between you
• If HMRC has told you that you are in its Managing Serious Defaulters programme: full accounts, a profit and loss account and a balance sheet MSD Rare
  Rare. Only applies if HMRC has written to say you are in this programme after a previous serious problem. Most landlords can tap ‘Not me’.