Filing your rental income on a Self Assessment return is much faster when the paperwork is already in one place. The scramble for a missing mortgage statement or a lost receipt is what turns a one-hour job into a lost weekend.
This is a practical checklist of everything you need before you start. It covers the income to report, the expenses you can claim, the records HMRC expects you to keep, and the figures that decide whether you owe tax at all.
It's written for individual UK landlords completing a Self Assessment return for the 2025/26 tax year. If you hold property through a limited company, the rules differ and you'll file company accounts and a Corporation Tax return instead.
There's also a short note at the end on Making Tax Digital for Income Tax, because the way many landlords keep records is about to change.
What documents do you need for a landlord tax return?
You need proof of every pound of rent received and every expense you want to claim, plus the details of any property you bought or sold in the year. Gather your income records, expense receipts, finance statements and ownership documents before you open the return.
Here's the full checklist, broken into the sections HMRC's property pages expect you to complete.
What rental income do you need to report?
Start with the money coming in. Report the rent you were entitled to in the tax year, not just what landed in your account, along with any other sums you received from the tenancy.
Pull together:
- Rent statements or a rent schedule for each property, covering 6 April 2025 to 5 April 2026.
- Letting agent statements, which usually show gross rent, their fees and the net amount paid to you. You report the gross rent and claim the fees as an expense, not just the net figure.
- Records of any deposits you kept to cover damage or unpaid rent, as these count as income.
- Other charges you billed tenants, such as fees for services, cleaning or use of furniture.
- Any insurance payouts that covered lost rent.
If you let a room in your own home, the rent-a-room scheme may apply instead, and that's a separate calculation.
A point worth getting right from the start: HMRC treats all your UK properties as a single UK property business. UK and overseas lettings are separate businesses and go on different parts of the return, so keep those figures apart from day one.
Which expenses can you claim as a landlord?
You can deduct costs that are wholly and exclusively for renting out the property. The big rule is the split between revenue costs, which you deduct in full against rental income, and capital costs, which you can't deduct here and instead affect your Capital Gains Tax position when you sell.
Gather receipts, invoices and statements for:
- Letting agent and property management fees.
- Repairs and maintenance that restore the property, such as fixing a boiler, repainting or replacing a broken window. Improvements that go beyond the original condition are capital, not repairs.
- Buildings and contents insurance.
- Council tax, gas, electricity and water where you pay them rather than the tenant.
- Ground rent and service charges on leasehold property.
- Accountancy and some legal and professional fees.
- Costs of services such as gardeners and cleaners.
- Phone calls, stationery and advertising for new tenants.
- Direct costs of running the lettings, including a reasonable proportion of vehicle running costs for property visits.
According to gov.uk's guidance on working out your rental income, these allowable expenses are deducted from your rental income to arrive at your taxable profit.
Can you claim for replacing furniture and appliances?
Yes, but only for replacements, not the first time you kit out a property. The old wear and tear allowance was withdrawn and replaced by replacement of domestic items relief from 6 April 2016 for Income Tax payers.
Under the relief, you can claim the cost of a like-for-like or nearest modern equivalent replacement of a domestic item such as a sofa, bed, carpet, fridge or crockery, plus the cost of disposing of the old item, less anything you got for it. You can't claim the initial cost of furnishing the property, and you have to strip out any element of improvement. So gather receipts for any replacements you made during the year.
How does mortgage interest relief work now?
This is the area landlords most often get wrong, so it's worth a careful check. You can no longer deduct mortgage interest and other finance costs as a normal expense.
Since 6 April 2020, Income Tax relief on residential property finance costs has been restricted to the basic rate of Income Tax, currently 20% for 2025/26. Instead of reducing your taxable rental profit, your finance costs give you a tax reduction worth 20% of those costs, applied after your tax is calculated.
Finance costs include interest on buy-to-let mortgages, loans and overdrafts taken out for the property, plus fees for arranging that finance.
So your checklist here is your annual mortgage interest statements for each property, showing the interest charged in the year. Don't lump the interest in with your other expenses. Keep it separate, because it goes in its own box and is treated differently.
This restriction applies to residential lettings held personally. It doesn't apply to companies, and the treatment of non-residential property differs.
Should you claim the £1,000 property allowance instead?
There's a flat property allowance of £1,000 a year that you can use instead of claiming actual expenses, verified on gov.uk's rental income guidance.
How it works:
- If your total property income for the year is £1,000 or less, it's normally tax-free and you may not need to report it at all.
- If your income is more than £1,000, you can choose to deduct the £1,000 allowance instead of your actual expenses.
- You can't do both. If you claim the property allowance, you can't also deduct your expenses.
So the allowance only helps if your real expenses are less than £1,000. For most landlords with a mortgage, agent fees and insurance, actual expenses are far higher, so claiming real costs gives a bigger deduction. Run both figures before you decide.
What records does HMRC expect you to keep?
You need records that back up every figure on your return, and you need to keep them after you file in case HMRC asks to see them.
Hold on to:
- Rent records and bank statements showing money received.
- Receipts and invoices for every expense claimed.
- Mortgage interest statements.
- Completion statements and solicitor invoices for any property bought or sold in the year.
- Records of furniture and appliance replacements.
Keep these for at least five years after the 31 January filing deadline for that tax year, in line with HMRC's Self Assessment record-keeping requirements. If you've started keeping digital records for Making Tax Digital, the same source documents still matter.
Illustrative example: working out a rental profit
Here's how the pieces fit together. The figures are illustrative.
Illustrative example. Priya is a higher-rate taxpayer who lets one flat for the whole of 2025/26. She receives £15,000 in rent. Her allowable expenses are £2,000 of agent fees, £600 insurance and £900 of repairs, totalling £3,500. She also pays £4,000 of buy-to-let mortgage interest, which is a finance cost.
Her taxable rental profit is the rent less the allowable expenses:
| Item | Amount |
|---|---|
| Rental income | £15,000 |
| Less agent fees | -£2,000 |
| Less insurance | -£600 |
| Less repairs | -£900 |
| Taxable rental profit | £11,500 |
As a higher-rate taxpayer, the Income Tax on that £11,500 profit is 40%, which is £4,600.
The £4,000 mortgage interest is not deducted above. Instead it gives a basic-rate tax reduction of 20% of £4,000, which is £800.
So her Income Tax on the rental profit is £4,600 less the £800 finance-cost reduction, which is £3,800. This sits on top of the tax on her other income, and the 40% and 20% rates used here are the 2025/26 Income Tax rates. The example ignores her personal allowance and other income to keep the rental mechanics clear.
The takeaway: if Priya had wrongly treated the £4,000 interest as a normal expense, she'd have understated her profit and her tax. Keeping finance costs separate is the single most common fix we make on landlord returns.
When are the deadlines and what are the penalties?
For a paper return the deadline is midnight on 31 October following the end of the tax year, and for an online return it's midnight on 31 January. Any tax you owe is also due by 31 January. For 2025/26, the online filing and payment deadline is 31 January 2027.
If you've never filed before, you must register for Self Assessment by 5 October following the end of the tax year, so by 5 October 2026 for the 2025/26 year.
Miss the filing deadline and the penalties stack up. According to gov.uk's Self Assessment penalties guidance:
| How late | Penalty |
|---|---|
| 1 day late | £100 fixed penalty |
| 3 months late | £10 a day, up to £900 |
| 6 months late | 5% of tax due or £300, whichever is greater |
| 12 months late | A further 5% or £300, whichever is greater |
Paying late is charged separately, with penalties of 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest on the amount owed. The simplest way to avoid all of this is to have the checklist above ready well before January.
How does Making Tax Digital change this checklist?
The documents you gather won't change, but how you record them is about to. This is the MTD-readiness note.
Making Tax Digital for Income Tax started on 6 April 2026. From that date, sole traders and landlords with qualifying income over £50,000 must keep digital records and send quarterly updates to HMRC using compatible software. The threshold falls to £30,000 from April 2027 and £20,000 from April 2028.
A few points that matter for landlords:
- Qualifying income is your gross income, before expenses, and it adds together your self-employment and property income. Rent counts towards the threshold even if your taxable profit is small.
- The quarterly updates are cumulative year-to-date summaries, not four separate tax returns. According to gov.uk's quarterly updates guidance, each update covers from the start of the tax year to the end of the update period, with standard deadlines of 7 August, 7 November, 7 February and 7 May.
- After the year ends you submit a final declaration, which replaces the Self Assessment return and is where you claim reliefs such as the finance-cost reduction. It's due by 31 January after the tax year.
- You'll need to keep records digitally with digital links between programs, so manual copy-paste between a spreadsheet and your filing software won't be allowed. Spreadsheets can still work, but only with bridging software.
If your rental income is near or over £50,000, the practical move now is to get your bookkeeping into compatible software so the quarterly habit is in place before you're mandated. HMRC maintains a list of compatible software, so check that before committing to a product.
To see whether and when MTD applies to you, use gov.uk's eligibility checker.
Frequently asked questions
Do I need to file a tax return if I only made a small rental profit?
If your property income is more than £1,000 in the year, you generally need to report it through Self Assessment, even if the profit after expenses is small. Income of £1,000 or less is usually covered by the property allowance and may not need reporting. If your rental income reaches £50,000 or more, you also fall within Making Tax Digital for Income Tax from 6 April 2026.
Can I deduct my buy-to-let mortgage payments?
You can't deduct the capital repayment part of your mortgage at all, and you can't deduct the interest as a normal expense either. Since 6 April 2020, residential finance costs only give a tax reduction worth 20% of the interest for 2025/26, applied after your tax is worked out. Keep your annual interest statement separate so it goes in the right box.
What's the difference between a repair and an improvement?
A repair restores the property to its previous condition, such as mending a roof or replacing a broken boiler with a similar one, and is deductible against rental income. An improvement makes the property better than before, such as adding an extension or upgrading to a higher standard, and is a capital cost you can't deduct here. Capital costs may instead reduce your Capital Gains Tax when you sell.
Should I use the £1,000 property allowance or claim actual expenses?
Use whichever gives the bigger deduction. The £1,000 property allowance only beats your real costs if your actual expenses are below £1,000, which is rare once you factor in agent fees, insurance and repairs. You can't claim both, so work out your taxable profit each way and pick the lower one.
When is my 2025/26 landlord tax return due?
The online filing deadline and the payment deadline are both 31 January 2027 for the 2025/26 tax year. A paper return is due earlier, by 31 October 2026. If you've never filed before, register for Self Assessment by 5 October 2026.
Do I need to report UK and overseas rental property separately?
Yes. All your UK properties form one UK property business, but overseas property is a separate business reported in a different part of the return. Keep the income and expenses for each apart from the start so the figures don't get mixed.
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Get your landlord return done properly
A clean checklist is half the battle, but the finance-cost rules, the repair-versus-improvement line and the new Making Tax Digital obligations are where landlords lose money or trip up.
If you'd like that handled, Zmartly's self assessment services and our accounting support for landlords cover the full return, the record-keeping and getting you MTD-ready. Book a call with a Zmartly accountant and we'll tell you exactly what to gather and file it for you.
