If you let a property for the first time during the 2025 to 2026 tax year, the date in your head is probably 31 January. That is the filing deadline, and it is the one every article is about in December.
The one that catches people is five months earlier.
You have to tell HMRC by 5 October 2026 that you need to complete a tax return for the year that ended on 5 April 2026. GOV.UK puts it plainly: if you tell HMRC after 5 October, you could get a penalty. Registering is not filing. It is asking for the account you will file into, and it takes a fortnight or so to come back with the reference you need.
Not tax advice. These are the published deadlines and thresholds as at August 2026. Where the sums are close to a threshold or the ownership is unusual, use an accountant.
First: do you have to file at all?
Not every landlord does. GOV.UK sets out three figures.
The first £1,000 of property income is tax-free. That is the property allowance. Under it, with no other reason to file, you generally have nothing to do.
Between £1,000 and £2,500, GOV.UK tells you to contact HMRC rather than assume a full return is needed.
You must send a Self Assessment return if your rental income is more than £2,500 after allowable expenses, or more than £10,000 before allowable expenses. Note the two are different tests, on different sides of your costs, and either one triggers it. A landlord with £11,000 of rent and £9,000 of costs is over the second test even though the profit is small.
Both figures are income from property, so a single room let and a whole flat count the same way.
The calendar, in the order it happens
| Date | What |
|---|---|
| 5 October 2026 | Tell HMRC you need to file for 2025-26. Registration, not the return. |
| 31 October 2026 | Paper return deadline, if you file on paper. |
| 30 December 2026 | Deadline if you want tax under £3,000 collected through your PAYE code instead of as a lump sum. |
| 31 January 2027 | Online return and payment of the tax owed. |
| 31 July 2027 | Second payment on account, if you have one. |
Two things people misread. The 31 January date is both the filing and the payment deadline, so filing on the 30th and paying in March is still late payment. And the 30 December route only works if you file online by then and the amount is under the limit, which is why it quietly disappears for most people who leave it to January.
The January bill is usually bigger than the tax you owe
This is the part that surprises first-time landlords, and it is worth understanding in August rather than on 30 January.
If your Self Assessment bill is £1,000 or more, HMRC generally asks for payments on account: advance instalments towards the following year. They fall due on 31 January and 31 July, and each is usually half of the tax you owed the previous year.
In your first year that means the January payment can be one and a half times the tax for the year just gone: the balance for 2025-26, plus the first instalment for 2026-27.
You are not asked for payments on account if either of these is true:
That second one catches a lot of employed landlords with a small rental profit, which is worth checking before you assume the worst.
What you actually fill in
Rental income goes on the property pages of the Self Assessment return, referred to as SA105 when filed on paper. They ask for the income, the allowable expenses split into categories, and the residential finance-costs figure that is treated as a basic-rate reduction rather than a deduction, which is the Section 24 change landlords still get caught by.
The work is not the form. The work is having the figures in categories that match it, which is much easier if you were categorising as you went than if you are sorting a shoebox in January. Our expenses and deductions guide covers what goes where and, more usefully, what does not count.
Where MTD fits, and why it is probably not your problem yet
Making Tax Digital for Income Tax is a different regime with quarterly updates, and it phases in by income level. If you are filing your first return for 2025-26, you are filing a normal Self Assessment return and the January deadline is the one that applies to you.
It is worth knowing where the line is, because the threshold is tested on an earlier year and people are caught by that rather than by the rule itself. We keep that separate: MTD for landlords has the thresholds and dates, and the myths post deals with the things that are repeated and wrong.
Do not let a quarterly-updates article convince you that you have missed something for 2025-26. Register, then file.
If you let in earlier years and never told them
This is more common than people admit, and there is a defined route rather than a cliff. GOV.UK lets you tell HMRC about rental income from previous years, gives you a disclosure reference number, and then allows three months to work out what you owe and pay it.
Going to them is materially better than being found. The information HMRC receives from deposit schemes, letting agents and the Land Registry makes "they will not know" a poor plan.
What to have ready before you start
Doing the collecting during the year instead of in January
None of the above is difficult. It is only unpleasant because it is done once a year, from memory, against a deadline.
In LetCompliance rent is logged as it is paid, expenses are captured when they happen (photograph the receipt and it is read and categorised), and the figures come out at the end of the year already sorted into the categories the property pages ask for. It does not file for you, and nothing does: it gets you to the return with the numbers ready rather than with a folder.
Common questions
When do I have to tell HMRC I am letting a property? By 5 October following the end of the tax year in which you had the rental income. For income in 2025-26, that is 5 October 2026. GOV.UK warns that telling them later could result in a penalty.
Do I need to file if I only made a small profit? You must file if rental income was more than £2,500 after allowable expenses, or more than £10,000 before allowable expenses. Under £1,000 of property income is covered by the property allowance. Between £1,000 and £2,500, GOV.UK asks you to contact HMRC.
Why is my January bill higher than my tax? Payments on account. If the bill is £1,000 or more you generally pay the balance for the year just ended plus a first instalment towards the next, so the January payment can be one and a half times the year's tax.
Can I avoid payments on account? They are not due if last year's tax was under £1,000, or if more than 80% of your tax was collected outside Self Assessment, such as through your PAYE code.
What is SA105? The property pages of the Self Assessment return, where rental income and expenses are reported.
I have been letting for years and never declared it. Tell HMRC about rental income from previous years. You get a disclosure reference number and three months to work out what you owe and pay it.
2026 UK Landlord Compliance Cheat Sheet
Every Gas Safety, EICR, EPC, deposit and Right to Rent deadline on one printable A4 page. Updated for the Renters’ Rights Act 2025.
- Every UK statutory deadline by document type
- Maximum penalty per breach (HSE, MEES, RtR, deposit)
- What blocks a Section 8 / Form 6A possession claim
- Print-friendly A4 with checkboxes
Frequently asked questions
When do I have to tell HMRC I am renting out a property?
By 5 October following the end of the tax year in which you had the rental income. For income received in the 2025 to 2026 tax year, which ended on 5 April 2026, the deadline is 5 October 2026. GOV.UK warns that if you tell HMRC after that date you could get a penalty. Registering is a separate step from filing: it gives you the account and reference you will later file into, so leaving it until January does not work.
Do I have to file a tax return on a small rental profit?
It depends on two separate tests and either one triggers a return. You must send a Self Assessment return if your rental income was more than £2,500 after allowable expenses, or more than £10,000 before allowable expenses. The first £1,000 of property income is tax-free under the property allowance. Between £1,000 and £2,500, GOV.UK asks you to contact HMRC rather than assume a full return is required.
What are the Self Assessment deadlines for a landlord in 2026 and 2027?
Register by 5 October 2026. A paper return must reach HMRC by 31 October 2026. If you want tax under £3,000 collected through your PAYE code instead, file online by 30 December 2026. The online return and the payment are both due by 31 January 2027. A second payment on account, where one applies, falls due on 31 July 2027.
Why is my first January tax bill bigger than the tax I owe?
Payments on account. Where the Self Assessment bill is £1,000 or more, HMRC generally asks for advance instalments towards the following year, due on 31 January and 31 July, each usually half of the tax you owed the previous year. In a first year that means January can be one and a half times the tax for the year just ended: the balance owed, plus the first instalment for the year in progress.
When do payments on account not apply?
They are not required if the tax you owed last year was less than £1,000, or if more than 80% of the tax you owed was collected outside Self Assessment, for example through your PAYE tax code. The second exemption catches many employed landlords with a modest rental profit.
Does Making Tax Digital apply to my first return?
Making Tax Digital for Income Tax is a separate regime with quarterly updates, phased in by income level and tested against an earlier tax year. A landlord filing a first return for 2025 to 2026 is filing an ordinary Self Assessment return, with 31 January 2027 as the deadline. Check the MTD thresholds separately rather than assuming a quarterly-updates article applies to the year you are filing.
I have been letting for years and never declared it. What now?
There is a defined route. You can tell HMRC about rental income from previous years, and you are given a disclosure reference number and three months to work out what you owe and pay it. Coming forward is materially better than being found, given what HMRC already receives from deposit schemes, letting agents and the Land Registry.