How do I file a Self Assessment tax return for the first time as a landlord?

Add up your 2025-26 rent and costs, fill in the UK property pages (SA105) of your tax return, then file online by 31 January 2027 and pay any tax owed by the same date.

This page covers what differs for landlords in England, from GOV.UK and HMRC's 2025-26 property notes, checked on 18 October 2026. For your Unique Taxpayer Reference (UTR), sign-in and the main return, see filing your first return.

Where your figures go

HMRC's notes set out the boxes:

Expenses or the £1,000 allowance

You choose one. The property allowance lets you deduct up to £1,000 instead of your actual costs, but not more than your income. If you claim it, you cannot deduct any expenses or claim other allowances. GOV.UK says you cannot use it if you claim the tax reduction for mortgage interest, or if any rent comes from your or your spouse's or civil partner's employer, or a company or partnership that you, or someone connected to you, owns, controls or is a partner in.

Costs over £1,000 give the bigger deduction. With a mortgage, work out the tax both ways.

The cash basis is the starting point

For most landlords letting personally, the cash basis is the default: rent counts when received and costs when paid. You can only use it if your UK property income is up to £150,000, cut pro rata for a part year. Above that, or if you choose, you use traditional accounting and put an X in box 20.2. If you and your spouse or civil partner are taxed 50:50 on a joint let, you must both use the same basis.

Mortgage interest is a tax reduction

Mortgage interest and loan costs on a residential let are not expenses: they go in box 44. HMRC then gives a tax reduction at the basic rate, 20%, on the lowest of your finance costs, your property profits and your income, excluding savings and dividends, above the personal allowance. Any unused amount is carried forward. Capital repayments do not count.

Repairs, improvements and replacements

A repair puts something back to its original condition and is an expense. Improvements to a residential let, such as an extension, are capital costs and cannot be claimed against rent, though they may count for Capital Gains Tax when you sell.

Replacement of domestic items relief (box 36) covers replacing furniture, furnishings, appliances and kitchenware used only by the tenant, once the old item is no longer available to them. It does not cover first purchases. If the new item is an upgrade, you claim only what a like-for-like replacement would cost.

Joint lets and rooms in your home

Each owner puts only their own share of income and expenses on their return. If you live with your spouse or civil partner, you are usually taxed in equal shares. To be taxed on unequal ownership shares instead, you both make a Form 17 declaration, with evidence of your shares, and HMRC must get it within 60 days of its date. It only covers income from that date. Other co-owners are usually taxed on their ownership share unless they agree a different split.

If you let furnished rooms in your own home for £7,500 or less (£3,750 if shared), put an X in box 4; if that is your only letting income, the rest of the pages can stay blank. See the Rent a Room Scheme.

Records, dates and penalties

Keep let dates, rent, costs, rent books, receipts, invoices and bank statements for at least 5 years after the 31 January deadline: for 2025-26, until at least the end of January 2032.

If you do not usually send a return, register by 5 October after the tax year you first had rent: 5 October 2026 for 2025-26. If you register later, HMRC's letter or email gives a filing deadline 3 months from its date, but the tax is still due by 31 January 2027. Paper returns were due by 31 October 2026.

Payments on account apply unless your bill was under £1,000 or over 80% was paid outside Self Assessment. Each is usually half of last year's bill, due by 31 January and 31 July. So 31 January 2027 can bring your whole 2025-26 bill plus half of it again.

A late return costs £100, then £10 a day after 3 months up to £900, then the greater of 5% of the tax due or £300 at 6 and 12 months. Late payment brings 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest.

What this means for you

This return decides when Making Tax Digital for Income Tax (MTD) starts for you. Qualifying income is your property and self-employment income added together, before expenses, using only your share of a joint let. Over £30,000 in 2025-26 means you start on 6 April 2027, with the first quarterly update due by 7 August 2027. Over £20,000 in 2026-27 means 6 April 2028.

If you started letting part-way through 2025-26, scale your property income up to a full year yourself. A flat let from 6 October 2025 at £2,600 a month took £15,600 by 5 April 2026, which is £31,200 over a full year, over £30,000.

Steps to file your first landlord return

1. Check you are registered and have your UTR and HMRC online sign-in.
2. Add up the 2025-26 rent you received, using your share for a joint let.
3. Sort costs into running costs, replacements, improvements and mortgage interest.
4. Choose between your running costs and the £1,000 allowance.
5. Fill in the UK property pages: rent in box 20, costs in boxes 24 to 29 and 36, mortgage interest in box 44.
6. Submit and pay by 31 January 2027.
7. Run the free MTD check to see if MTD starts for you on 6 April 2027.

There are more guides in the landlord section. Our tax plans start once our HMRC registrations are complete. Until then you can join the waitlist, and no payment is taken.