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Self Assessment property income: what to report, which boxes, and when it’s due

Rental income goes on the UK property pages of a Self Assessment return - a supplementary section you add to the main return, known as the SA105. It is not a complicated form. What makes it awkward is that the figures it asks for are rarely the figures you have to hand, particularly if a letting agent collects your rent and sends you a statement.

This covers whether you have to file at all, the dates, what goes in which box, and the one part landlords consistently get wrong: reporting the amount that reached the bank instead of the rent.

Do you need to file a Self Assessment at all?

HMRC uses two thresholds, and you only need to breach one of them:

• Over £2,500 after allowable expenses - your profit.
• Over £10,000 before allowable expenses - your gross rent.

The second one catches people out. A property that grosses £12,000 a year and makes almost nothing after the mortgage, the agent and a bad year for repairs still needs a return, because the £10,000 test looks at rent before anything comes off it.

Below that:

• £1,000 or less of gross property income. HMRC’s wording is that this “is exempt from tax and does not need to be reported on a tax return”. You generally don’t need to tell them anything, unless there’s a reason you can’t use the allowance.
• Between £1,000 and £2,500 gross. HMRC asks you to contact them rather than register for Self Assessment straight off. They may collect the tax another way, usually through your PAYE code.

If you already file a return for another reason - you’re self-employed, or you have untaxed income elsewhere - the property pages go on it regardless of how small the rental is.

The £1,000 property allowance, and when it isn’t worth taking

The property allowance is £1,000 a year and it belongs to the person, not the property. If you own a place jointly, you’re each eligible for £1,000 against your own share of the gross rent.

The catch is that it’s an either/or. If you claim the allowance you can’t deduct any other expenses or allowances - so it only helps when your total costs for the year come to less than £1,000. For an agent-managed property that’s rare. Management commission at 10% on £900 a month is £1,080 of expense before you’ve paid for anything else, so claiming the allowance would cost you money. It suits a small, cheap, low-maintenance let, or a room in a property you manage yourself.

The Self Assessment deadlines for landlords

The tax year runs 6 April to 5 April. For the 2025 to 2026 tax year, which ended on 5 April 2026, the dates are:

The 5 October one is the deadline people miss, because it doesn’t feel like a deadline. It’s the date by which you have to tell HMRC you exist as a landlord, and it falls six months before the one everybody has in their diary. If you started letting a property during the 2025 to 2026 tax year and haven’t filed a return before, that’s the date that applies to you.

Registering takes a few days to come back with a Unique Taxpayer Reference, and you need that before you can file, so leaving it until January is genuinely risky rather than just tight.

What goes in which box on the UK property pages

The UK property pages have two halves, income then expenses, and then a short calculation section. Here are the boxes a residential landlord normally uses, as numbered on the 2025 to 2026 SA105.

One warning before the list: box numbers move between tax years. Boxes 5 to 19 used to hold the furnished holiday lettings section and are no longer in use at all. Always check the form for the year you’re actually filing.

Income

• Box 20 - total rents and other income from property. Gross rent. All of it, before the agent’s fees and before anything else comes off.
• Box 20.1 - property income allowance. Only if you’re claiming the £1,000 allowance instead of expenses.
• Box 20.2 - tick this if you used traditional accounting rather than cash basis. More on that below.

Expenses

• Box 24 - rent, rates, insurance and ground rents. Business rates, water rates, council tax where you pay it, buildings and contents insurance, ground rent, and insurance against loss of rent.
• Box 25 - property repairs and maintenance. Painting, damp treatment, roof repairs, furniture repairs, the plumber. Repairs only - improvements are capital and don’t go here.
• Box 26 - non-residential property finance costs. Not for a normal buy-to-let. This is the commercial equivalent, and residential interest goes in box 44 instead. Easy to click by mistake, since it is sitting in the middle of the expenses.
• Box 27 - legal, management and other professional fees. This is where your letting agent goes. HMRC’s notes say it covers “management fees paid to an agent for rent collection, advertising and administration”, along with accountancy and lease renewal costs.
• Box 28 - costs of services provided, including wages. Communal cleaning, gardening, and the wages of the people doing them.
• Box 29 - other allowable property expenses. The catch-all: stationery, phone, business travel, advertising for tenants.
• Box 36 - costs of replacing domestic items. Residential lettings only, and replacements only. The initial cost of furnishing a property doesn’t qualify.

Where mortgage interest goes - box 44

Mortgage interest is not an expense on this form. It sits on its own, well below the expenses section, in box 44, residential property finance costs. HMRC’s notes describe it as costs that “can be used to calculate a reduction in your Income Tax”, which is exactly what happens: the figure buys you a basic rate tax reduction, currently 20%, taken off your tax bill rather than off your profit.

That’s been the position since 6 April 2020, after a phase-in that started in 2017. Two things follow. Your taxable profit is calculated before any interest comes off, which for a higher rate taxpayer can push rental profit into a band that doesn’t reflect what you actually kept. And if your finance costs are larger than your profit in a given year, the unused part carries forward - there’s a separate box for that, box 45.

Enter the interest only. The capital repayment part of a mortgage payment has never been claimable in any form. Your lender’s annual interest certificate is where the figure comes from, and it is the one number in this entire guide that will never appear on a letting agent’s statement, because your agent doesn’t pay your mortgage.

The calculation

• Box 38 - adjusted profit for the year, worked out with the sheet in HMRC’s notes.
• Box 40 - taxable profit, which is box 38 minus any brought-forward loss you’re using.
• Box 41 and box 43 - the loss for the year, and the loss you’re carrying forward.

If a letting agent collects your rent

Here’s where a lot of returns go wrong. Your agent pays you a net figure - rent, less their commission, less the VAT on it, less whatever they paid out on your behalf. That number is on your bank statement, it is easy to find, and it is not what box 20 is asking for.

Box 20 wants the gross rent. Box 27 wants the agent’s fees. Report the net payment as your income and you have quietly understated both sides of the return. Your profit may even come out roughly right, which is what makes it hard to spot, but the return is wrong and the arithmetic behind it is wrong.

It is also usually wrong on profit, for reasons that aren’t obvious:

• A payout can include a balance carried forward from the previous statement, which is last-period money arriving in this period.
• Some agents hold back a float or reserve for future costs. That money is yours and the rent it came from is taxable, even though it hasn’t reached you.
• Money you’ve paid in yourself - a contribution towards a certificate, a top-up to a maintenance float - sits in the income half of a statement because to the agent’s cash account it is money in. It isn’t rent and it isn’t taxable.
• Arrears are printed but not collected. On cash basis, rent you haven’t received isn’t income.

Pulling those apart, line by line, is most of the work in a landlord’s tax return. The companion guide to allowable expenses walks through where each figure sits on a statement, with a worked example, and covers the costs that get missed.

Cash basis or traditional accounting?

Cash basis is the default and it’s the simpler of the two: you count rental income when it’s received and expenses when they’re paid. Nothing is recognised because it’s owed. You can use it as long as your total income from UK property is up to £150,000.

Traditional accounting recognises income and costs when they’re incurred, whether or not the money has moved. If you use it, tick box 20.2. Most individual landlords don’t, and the switch has knock-on adjustments in the year you make it.

The practical difference is at the edges of the tax year. Rent that a tenant owed on 5 April and paid on 8 April belongs in next year’s return on cash basis, and this year’s under traditional accounting. Same for a repair invoiced in March and paid in April.

If you own the property jointly

Each owner reports their own share on their own return - there is no joint return, and there’s a box on the form to tick to say the income is jointly let. Married couples and civil partners who live together “will usually be taxed in equal shares”, whatever the deeds say. To be taxed on unequal shares instead you have to actually own it in those shares, be entitled to the income in the same shares, and tell HMRC using form 17, with evidence. Unmarried joint owners report according to their actual beneficial shares.

The £1,000 property allowance is per person, so each owner gets their own against their share of the gross rent.

Where Making Tax Digital fits

Making Tax Digital for Income Tax started phasing in from April 2026, for qualifying income over £50,000, then £30,000 from April 2027 and £20,000 from April 2028. Qualifying income is turnover from self-employment and property combined, measured before expenses.

It doesn’t replace the tax return. You send four short quarterly updates during the year and still make a final declaration after the year ends, and 31 January is still 31 January. What it changes is that you need the figures four times a year instead of once, and you’re expected to keep the records digitally rather than retyping them from a PDF. There’s more on this in the guide to MTD for landlords who use a letting agent.

Questions people ask

Before you start filling anything in

Get four things together first, and the form takes an evening rather than a weekend: every statement from your agent for the tax year, checked for gaps - a missing month is the most common cause of a wrong rent figure; your lender’s annual interest certificate; receipts or invoices for anything you paid for directly, outside the agent; and last year’s return, for any loss you’re carrying forward.

If you’re registering for the first time, do that before 5 October, because the rest of it is no use without a UTR.

Before you rely on any of this

This guide explains how the property pages work; it isn’t tax advice, and box numbers, thresholds and allowances change between tax years. Check the current UK property pages and notes on gov.uk for the year you’re filing, or ask an accountant.