Landlord Self Assessment basics: rent, expenses and Section 24

Published June 2026 · 8 min read

Plenty of tradespeople end up landlords — a flat kept after moving, an inherited house, a deliberate investment. Property income has its own tax rules, its own quirks (Section 24 chief among them), and it stacks on top of your trade income at Self Assessment time. Here are the basics in plain English. General information only — your accountant should confirm your own position.

Do you need to declare it?

Broadly: gross rental income under £1,000 a year is covered by the property allowance and may need no return at all. Above that, it goes on your Self Assessment. Your “rental business” is all your let properties combined — profits and losses pool across them.

What counts as rental income

All rent received, plus things like non-refunded deposits and payments for services. On the cash basis (the default for most individual landlords, and SubReady’s default too), you count rent when it’s received, not when it was due — which also means a missed month isn’t taxed until it arrives.

Expenses landlords can claim

• Repairs and maintenance — fixing, repainting, replacing like-for-like (a new boiler replacing a broken one). Improvements that upgrade the property (an extension) are capital, not a rental expense.
• Letting agent fees and management charges.
• Insurance — landlord, buildings, contents.
• Ground rent, service charges, and utilities or council tax you (not the tenant) pay.
• Accountancy and admin — including software; and travel to inspect or maintain the property, e.g. at the 45p mileage rate.
• Replacement of domestic items — like-for-like furniture and appliance replacements in furnished lets.

Section 24: the mortgage interest rule

Since Section 24 phased in fully, individual landlords cannot deduct mortgage interest as an expense. Instead you get a basic-rate (20%) tax credit on the interest. If you’re a basic-rate taxpayer the outcome is often similar; for higher-rate taxpayers it stings, because relief is capped at 20% — and because the interest now sits inside your taxable income, it can even push you into higher rate. This single rule is why landlord tax estimates done on the back of an envelope are so often wrong. SubReady’s tax estimate handles Section 24 for you.

Deadlines and MTD

• Tax year: 6 April to 5 April. Online return and payment: 31 January. First-time? Register for Self Assessment by 5 October after the tax year you started letting.
• If your bill tops £1,000, payments on account apply.
• MTD counts property income. Combined self-employment + property turnover over £50,000 means quarterly digital updates from April 2026 (£30k from 2027, £20k from 2028) — see the MTD guide.

Keeping the records without a spreadsheet

On SubReady, property sits alongside your trade income as a separate income source:

• Add a property by message: “add property 7 Kestrel Close, rent 825”.
• Log rent as it lands: “rent 825 for Kestrel Close” — and SubReady’s missed-rent nudges notice when a month hasn’t appeared.
• Snap receipts for repairs and agent fees like any other expense, per property.
• The tax estimate keeps property income separate from trade income, with Section 24 applied — and the Annual Return presents both for your accountant.

Landlord questions worth answering straight

My rental makes a loss — do I still report it?

Yes, if you’re over the reporting threshold — and you’d want to anyway: property losses carry forward against future property profits, but only if they’re on the record.

The deposit — is that income?

Not while it’s held in a protection scheme to be returned. It becomes income only to the extent you keep it — for damage or unpaid rent — at the end of the tenancy.

My partner and I own the flat jointly — who declares what?

Joint owners generally each declare their share. How that share is set (especially for married couples) has rules of its own — a classic “confirm with your accountant” item.

What records should I actually keep?

Rent received per property per month, every cost with its receipt, mortgage interest statements, and agent statements. That’s precisely the set SubReady builds as you message things in — which is why the year-end conversation with your accountant gets short.

Rental income rewards the same habit as trade income: record things when they happen. Start the 14-day free trial and put the rent book in your pocket.