If you rent out property in the UK, HMRC expects to hear about it. For most landlords that means filing a Self Assessment tax return every year, with the rental income reported on the UK property pages, form SA105. The form isn’t long. The mistakes come from what goes into it: claiming mortgage interest as an expense, mixing up repairs with improvements, or splitting income with a partner the wrong way.
This guide covers who has to file, the deadlines, how the property pages work, and the rules that most often trip landlords up.
Do you need to file a landlord tax return?
You need to tell HMRC about rental income if your gross property income — rent before expenses — is more than £1,000 in a tax year. Below that, the property allowance covers it and you don’t need to report it.
- Gross rent over £1,000: you need to file a Self Assessment return.
- Gross rent between £1,000 and £2,500 with no other reason to file: you may be able to report it to HMRC through your tax code instead. Ask HMRC to confirm.
- Profit over £2,500 after expenses, or gross rent over £10,000: you must file a Self Assessment return.
Renting a room in your own home? The Rent-a-Room scheme may let you earn up to £7,500 a year tax-free instead.
Key deadlines for landlords
- 5 October after the tax year ends — register for Self Assessment if you’re new to it
- 31 October — paper returns
- 31 January — online returns, and payment of any tax due
- 31 July — second payment on account, if they apply to you
New landlords should register early. Your Unique Taxpayer Reference (UTR) arrives by post and can take a few weeks. See our registration guide for the steps.
The SA105 UK property pages: what goes where
The property pages ask for a summary for the year, not every transaction. Here’s what you’ll report.
1. Number of properties and income
Enter how many properties you let and the total rent received. Include any other money from the letting, such as payments for services you provide or non-refundable deposits you keep.
2. Allowable expenses
You can deduct costs incurred wholly for the letting business, including:
- Letting agent and management fees
- Repairs and maintenance (not improvements)
- Buildings and landlord insurance
- Ground rent and service charges
- Council tax and utilities, if you pay them for the tenant
- Accountancy fees and legal costs for renewing short leases
- Replacing domestic items such as furniture and appliances, on a like-for-like basis
Alternatively, you can claim the £1,000 property allowance instead of actual expenses. It’s usually only worth it if your real expenses are below £1,000.
3. Finance costs — reported separately
This is where many landlords go wrong. For residential lets held personally, mortgage interest is not deducted as an expense. You enter it in a separate finance costs box. HMRC then gives you a tax credit worth 20% of those costs.
For a basic-rate taxpayer this works out about the same as a deduction. For a higher-rate taxpayer it doesn’t: you pay 40% tax on profit before interest and only get 20% back. It’s the main reason some landlords hold property through a limited company. If you’re weighing this up, our landlord accountants can model both options for your portfolio.
4. Losses
If expenses exceed rent, the loss is carried forward and set against future rental profits from your property business. It can’t usually be set against your salary or other income.
Repairs vs improvements
Repairs keep a property in the condition it was in. Improvements make it better than it was. Replacing a broken boiler with a similar modern one is a repair. Adding an extension or a loft conversion is an improvement.
Improvements can’t be deducted from rental profit. Instead, they may reduce your Capital Gains Tax when you sell, so keep the invoices.
Jointly owned property
If you own a rental property with someone else, each owner reports their share on their own return. For married couples and civil partners, HMRC assumes a 50:50 split by default, even if you own the property in different shares. If your actual ownership is unequal, you can file a joint declaration on Form 17 so income is taxed according to your real shares. You must hold the beneficial interest in those proportions.
Records to keep
Keep rent statements, invoices, receipts, mortgage statements and agent reports for at least 5 years after the 31 January filing deadline for that tax year. Good records make the return quicker and protect you if HMRC opens an enquiry.
Making Tax Digital for landlords
Making Tax Digital for Income Tax changes the process for larger landlords. Since April 2026, landlords and sole traders with qualifying income over £50,000 must keep digital records and send quarterly updates. The threshold falls to £30,000 from April 2027. Qualifying income is your gross rent plus any self-employed turnover, not profit.
If you’re in scope, the SA105 return is replaced by quarterly updates and a year-end final declaration. Our guide to Making Tax Digital for landlords covers what changes and when.
Common landlord tax return mistakes
- Deducting mortgage capital repayments — only interest counts, and it goes in the finance costs box
- Claiming improvements as repairs
- Forgetting rental income from a property let while you lived abroad or between homes
- Splitting jointly owned income 50:50 when a Form 17 declaration reflects different shares
- Missing the 5 October registration deadline in your first year
Get your landlord tax return done for you
SmartFiling’s ICAEW chartered accountants prepare landlord tax returns for a fixed fee, including finance costs, joint ownership and MTD. See our Landlord Accountant service or get a free quote — we’ll reply within one working day.
Frequently asked questions
Do I pay National Insurance on rental income?
Usually not. Rental income is normally treated as investment income, not self-employment, unless you run a genuine property business with substantial services.
Can I deduct my mortgage payments?
No. Capital repayments are never deductible. Interest on a residential let gets a 20% tax credit instead of a deduction.
What if I only rented out my property for part of the year?
Report the rent you received and the expenses for the period it was let. You may also need to think about Capital Gains Tax if you later sell.
