Whether you own a single buy-to-let flat or a growing portfolio of rental properties, understanding how to declare your rental income to HMRC is one of the most important responsibilities you face as a UK landlord. Getting it right protects you from penalties, helps you claim legitimate deductions, and keeps your finances on solid ground.

This guide walks through the key steps, allowable expenses, and common pitfalls so you can approach your next self-assessment return with confidence.

Who Needs to Declare Rental Income?

If you receive rental income from property in the UK, you are generally required to report it to HMRC through a self-assessment tax return. This applies whether you rent out a house, a flat, a room under a separate letting arrangement, or a holiday let.

The property income allowance is a tax-free allowance of £1,000 per tax year. If your total gross rental income is below this threshold, you do not need to declare it to HMRC. However, if you choose to use the allowance when your income exceeds £1,000, you take it as a flat deduction in place of actual expenses -- you cannot use both the allowance and itemised expenses in the same tax year.

Most landlords with regular tenancies will exceed the £1,000 threshold and must register for self-assessment if they have not already done so.

Registering for Self-Assessment

If you are a first-time landlord, you must register with HMRC for self-assessment by 5 October following the end of the tax year in which you first received rental income. The UK tax year runs from 6 April to 5 April. For example, if you began receiving rental income during the 2025/26 tax year (which ends 5 April 2026), you must register by 5 October 2026.

Once registered, you will receive a Unique Taxpayer Reference (UTR) and can file your return online through the HMRC self-assessment portal.

Key Deadlines

The main deadlines for self-assessment are:

  • 31 October -- deadline for filing a paper tax return
  • 31 January -- deadline for filing an online tax return
  • 31 January -- deadline for paying any tax due for the previous tax year

For the 2025/26 tax year (ending 5 April 2026), the online filing deadline is 31 January 2027. Late filing incurs an automatic £100 penalty, with further daily penalties if the delay continues. Interest accrues on unpaid tax from 1 February.

Making Tax Digital for Income Tax

From 6 April 2026, Making Tax Digital for Income Tax Self Assessment (MTD for ITSA) becomes mandatory for landlords and sole traders with combined property and self-employment income exceeding £50,000 per year. Under MTD, affected landlords must:

  • Keep digital records of income and expenses
  • Submit four quarterly updates to HMRC each year using MTD-compatible software
  • Submit a final declaration by 31 January after the tax year ends

The income threshold reduces to £30,000 from 6 April 2027 and to £20,000 from 6 April 2028. Landlords approaching these thresholds should begin planning for compliance now.

Calculating Your Taxable Rental Income

Your taxable rental income is your gross rental receipts minus your allowable expenses. Detailed record-keeping throughout the year is essential.

What Counts as Rental Income

Rental income includes all payments you receive in connection with the letting, including:

  • Regular rent payments
  • Payments for use of furniture
  • Charges for services such as cleaning of common areas or garden maintenance that you pass on to tenants

Allowable Expenses

HMRC allows landlords to deduct costs that are incurred wholly and exclusively for the purpose of letting the property. Common allowable expenses include:

  • Letting agent fees and property management costs
  • Building and contents insurance premiums
  • Maintenance and repair costs -- costs of restoring the property to its original condition. Note that improvements (enhancing beyond the original condition) are not deductible as revenue expenses, though they may reduce Capital Gains Tax on eventual sale.
  • Council tax, water rates, and utility bills you pay on behalf of tenants
  • Accountancy and legal fees related to the letting (but not the costs of buying the property)
  • Ground rent and service charges for leasehold properties
  • Advertising costs for finding tenants
  • Travel costs for visiting the property to carry out inspections or repairs (at HMRC-approved mileage rates)

The Finance Cost Restriction (Section 24)

Since 6 April 2020, individual landlords can no longer deduct mortgage interest and other residential property finance costs as a direct expense. Instead, under what is commonly called the Section 24 restriction, you receive a tax credit at the basic rate (20%) on your finance costs. This means:

  • Higher rate taxpayers (40%) and additional rate taxpayers (45%) no longer receive relief at their marginal rate on mortgage interest
  • The restriction applies to mortgage interest, loan arrangement fees, and overdraft interest related to the letting
  • The restriction applies to individuals and partnerships, not to companies letting residential property

Replacement of Domestic Items Relief

For furnished lettings, you cannot claim a wear-and-tear allowance. Instead, you may claim the cost of replacing domestic items such as furniture, appliances, and kitchenware under the Replacement of Domestic Items Relief. You can only claim when genuinely replacing an existing item, not when providing one for the first time, and the replacement must be of a similar standard (if you upgrade significantly, only the cost of a like-for-like replacement is deductible).

Reporting Your Rental Income

Rental income from UK property is reported on the SA105 (UK Property) supplementary pages of your self-assessment tax return. If you also have overseas rental income, that is reported separately on the SA106 pages.

Payments on Account

If your income tax and Class 4 National Insurance bill (after tax credits and deductions) is more than £1,000 per year and less than 80% of your total tax liability is collected at source, HMRC will require you to make payments on account -- two advance payments towards your next year's tax bill, each equal to half of the previous year's liability. These are due on 31 January and 31 July. This can catch new landlords off guard, as the first payment on account is due at the same time as the previous year's balancing payment.

Record-Keeping

HMRC requires landlords to keep records for at least five years after the 31 January submission deadline for the relevant tax year. Good records include:

  • Rental agreements and tenancy contracts
  • Bank statements showing rental payments received
  • Receipts and invoices for all expenses
  • Mortgage statements showing interest paid
  • Gas safety certificates, EICR reports, and other compliance documents
  • Correspondence with tenants and agents

From April 2026, landlords caught by MTD for ITSA must keep digital records.

Renting a Room in Your Own Home

If you rent out a furnished room in your own home, the Rent a Room scheme provides a tax-free allowance of £7,500 per year (£3,750 if two people share the income from the same property). If your income from the room exceeds this threshold, you must declare the excess via self-assessment.

How Cleemo Helps UK Landlords

Cleemo is designed to simplify the financial side of property management. With Cleemo you can:

  • Track rental payments automatically -- see at a glance which tenants have paid and which are overdue
  • Generate rent receipts that satisfy both your tenants' needs and your own record-keeping requirements
  • Categorise expenses so you have a clear summary of allowable deductions at tax time
  • Store documents digitally -- tenancy agreements, invoices, and receipts all in one place
  • Monitor your portfolio across multiple properties from a single dashboard
  • Export financial summaries for your accountant or MTD-compatible software

Frequently Asked Questions

Can I offset losses from one property against income from another?

Yes. If one property makes a loss in a tax year, you can offset that loss against profits from other UK rental properties in the same year. Any remaining loss can generally be carried forward and set against future rental profits.

What happens if I forget to declare rental income?

HMRC can charge penalties for failure to notify, late filing, and inaccuracies. If you have undeclared income from previous years, making a voluntary disclosure will generally result in a lower penalty than being discovered through an investigation.

Do I need an accountant for rental income?

There is no legal requirement to use an accountant, but many landlords find professional advice helpful, particularly when portfolios grow or when the Section 24 restrictions affect their tax position. A good property management tool like Cleemo can significantly reduce the bookkeeping burden.

Does the Section 24 restriction apply to company landlords?

No. The finance cost restriction applies to individual landlords and partnerships. Companies that let residential property can still deduct mortgage interest as a business expense, though the overall tax position of operating through a company is complex and depends on individual circumstances.

Conclusion

Declaring rental income correctly is a legal requirement that carries real financial penalties if you get it wrong. With proper record-keeping, a clear understanding of allowable expenses, and awareness of the Section 24 restriction, the process need not be daunting.

Start by keeping meticulous records from day one, understand which expenses you can deduct, and file your return on time. As Making Tax Digital for ITSA approaches, choosing digital tools like Cleemo puts you well ahead of the mandatory requirements.

👉 Register at cleemo.com