SA105 Form: Box-by-Box Landlord Guide (2025/26)

The SA105 is the HMRC supplementary page you attach to your Self Assessment tax return (SA100) to declare UK property income. If you received rent from a UK property at any point during the tax year, you need to complete it — even if you made a loss.

It is not a complicated form, but the way you complete it has real consequences. Finance costs, repairs versus improvements, and losses carried forward are all reported differently than most landlords expect. This guide walks through every section with the information you actually need.

Who Needs to Complete the SA105

You must complete the SA105 if you received income from:

• Residential rental properties (flats, houses, HMOs)
• Furnished holiday lettings (FHL) — reported in a separate section of the same form
• Leasing land, garages, or parking spaces
• Grants of leases (premium payments)
• Commercial property

You do not need a separate SA105 for each property. HMRC treats all UK residential properties as a single property business. Combine all income and all expenses across every property and enter the totals.

You will need to register for Self Assessment and complete an SA100 (main return) alongside the SA105. If you have not yet registered, do so at www.gov.uk/register-for-self-assessment. Registration deadlines are 5 October following the end of the tax year in which you first received rental income.

Where to Find the SA105

Online: HMRC’s online Self Assessment service automatically prompts you to complete the UK property pages when you tick the relevant box in your SA100. The software generates the equivalent of SA105 digitally. Log in at www.gov.uk/log-in-file-self-assessment-tax-return.

Paper: Download the SA105 PDF from HMRC’s website for the current tax year. The paper filing deadline is 31 October; missing it means HMRC will process your return but you lose the option to pay via PAYE coding.

Third-party software: MTD-compatible tools such as GoSimpleTax, Hammock, and FreeAgent can file the SA105 equivalent digitally. From April 2026, landlords with property income over £50,000 must use compatible software for quarterly updates under Making Tax Digital.

Section by Section: UK Property Income

Income Boxes

Number of properties rented out — Enter the total number of properties you let during the year. If you let one property for only part of the year, still count it.

Total rents and other income from property — Enter your gross rental income: rent actually received during the tax year (April 6 to April 5), plus any other receipts such as tenant-paid bills you collected, insurance payments for lost rent, or compensation payments. This is a cash-basis figure for most landlords. Do not net off expenses here.

Tax taken off income — Almost always zero for residential landlords. This box applies where a payer has withheld tax at source, which is rare for standard property income.

Premiums for the grant of a lease — If you received a premium (lump sum) to grant a lease, part of that premium is treated as income. The taxable element depends on the lease length: for leases under 50 years, use the formula premium × (50 − lease years) / 50. Enter only the income element here, not the full premium.

Property Expenses Boxes

This is where you offset your legitimate costs against rental income. The golden rule is that every expense must be wholly and exclusively incurred for the rental business.

Rent, rates, insurance, ground rents — Service charges payable to a freeholder, buildings insurance, contents insurance for furnished lets, ground rent, and council tax during void periods you paid.

Property repairs and maintenance — Work that restores the property to its original condition: fixing a broken boiler, repainting, repairing a damaged roof section, replacing like-for-like fixtures. Read our allowable expenses guide for worked examples of the repair-versus-improvement line.

Non-residential finance costs — Interest on loans used for commercial or mixed-use properties, and finance costs not covered by the residential restriction. Most buy-to-let landlords leave this blank.

Residential finance costs — This is not a direct deduction. Enter your total mortgage interest and other residential finance costs (loan arrangement fees can be included here over the loan term). HMRC uses this figure to calculate your 20% basic-rate tax credit under Section 24. Do not include capital repayments — only the interest element.

Legal, management, and professional fees — Letting agent fees (management and finder fees), accountancy fees for the rental accounts, legal fees for tenancy agreements, and rent recovery costs are all claimable here. Fees for renewing a lease of over 50 years are capital, not revenue, so do not enter those.

Cost of services, including wages — If you pay a cleaner, gardener, or maintenance person to service the property, their wages or invoiced costs go here. This includes fees paid to a property manager beyond the percentages counted as letting agent fees.

Other allowable property expenses — Everything legitimately incurred that doesn’t fit the categories above: advertising costs for finding tenants, travel to inspect or maintain the property (at HMRC mileage rates — 45p per mile for the first 10,000 miles), stationery, phone costs (the rental-related portion), and subscriptions to landlord associations. See the complete landlord tax deductions list for every claimable item.

Section 24 Finance Costs: What Actually Happens

This is where most landlords make errors. Section 24 of the Finance (No. 2) Act 2015 was phased in from April 2017 and has been fully effective since April 2020.

How the tax credit works:

1. You enter gross rental income in the income box
2. You enter all expenses except mortgage interest in the expense boxes
3. You enter total mortgage interest in the residential finance costs box
4. HMRC calculates your rental profit without subtracting mortgage interest
5. You pay income tax on that higher profit
6. HMRC then applies a credit of 20% of the mortgage interest against your tax bill

Worked example:

	Before Section 24	Under Section 24
Rental income	£18,000	£18,000
Mortgage interest	£9,000	£9,000
Other expenses	£3,000	£3,000
Taxable profit	£6,000	£15,000
Tax at 40%	£2,400	£6,000
Less: 20% credit on interest	—	−£1,800
Tax payable	£2,400	£4,200

Higher-rate taxpayers pay 75% more tax on the same rental income. If this affects you, the buy-to-let limited company structure may significantly reduce your liability, since companies can still deduct mortgage interest in full.

Calculating Your Profit or Loss

Once you’ve entered income and expenses, the form calculates:

Income minus allowable expenses — Rental income less the expense boxes (excluding finance costs). This is your pre-finance-cost profit.

Rent a Room exempt amount — If you let a furnished room in your own home and your gross receipts are at or below £7,500, enter £7,500 (or £3,750 if jointly let). Your income becomes exempt and no further tax is due. If your receipts exceed £7,500, calculate tax under both the standard method (income minus expenses) and the Rent a Room method (excess over £7,500), and choose whichever gives a lower bill.

Private use adjustment — If you use the property yourself for any part of the year (holiday home, for example), you must restrict expenses proportionally to the days it was let. For example, if you let it for 200 days and used it personally for 100 days, only 200/300 of expenses are deductible.

Losses brought forward — If your rental business made a loss in a previous year, enter it here. It offsets this year’s profit. You can carry property losses forward indefinitely against future property profits, but you cannot offset them against other income.

Taxable profit (or loss to carry forward) — The final figure. If it is a profit, it feeds into your total income on the SA100 and is taxed at your marginal rate. If it is a loss, it carries forward to the following year.

Furnished Holiday Lettings: Separate Section

FHL properties get their own section of the SA105 because they have different rules. Qualifying FHL properties must be:

• Available to let for at least 210 days in the tax year
• Actually let for at least 105 days
• Not let to the same person for more than 31 continuous days during the 155-day availability window

FHL profits are treated as trading income, not property income. This means:

• Mortgage interest is fully deductible (not restricted by Section 24)
• Capital allowances apply to furniture and equipment
• Losses can be offset against other FHL income (but not general property income)
• Profits count as earnings for pension contribution purposes

Note: The government confirmed in the 2024 Autumn Budget that FHL tax advantages will be abolished from 6 April 2025. For 2025/26 returns, FHL properties are treated as standard residential lets.

Losses: Carrying Forward and Using Them

If your rental business makes a loss — expenses exceed income — you cannot claim the loss against your salary or other income. The loss is ring-fenced to the property business and carried forward.

To use losses brought forward:

1. Enter the loss amount in the losses brought forward box
2. It automatically offsets against this year’s rental profit
3. If the current year also makes a loss, both losses combine and carry forward again

Keep a running log of losses with tax year references. HMRC may ask for evidence years later, particularly if you eventually sell the property and losses have accumulated over many years.

What Records to Keep

HMRC recommends keeping rental records for at least 5 years from the 31 January filing deadline. For the 2024/25 return (filed by 31 January 2026), keep records until at least 31 January 2031.

Keep:

• Rental agreements and rent receipts or bank statements showing rent received
• Invoices and receipts for every expense claimed
• Mortgage statements showing interest paid (most lenders provide annual summaries)
• Mileage logs for travel to the property
• Correspondence with letting agents including fee invoices
• Records of any work done, with invoices confirming it was a repair not an improvement

From April 2026, MTD-compatible digital records will become mandatory for landlords earning over £50,000. See our Making Tax Digital guide for compatible software options.

7 Mistakes That Trigger HMRC Enquiries

1. Claiming capital improvements as repairs. Fitting a new kitchen is capital; repairing broken kitchen tiles is revenue. HMRC queries large repair figures relative to property value.

2. Deducting the full mortgage payment rather than just interest. Capital repayment is not an expense. Only the interest element belongs on the SA105.

3. Forgetting to include ALL rental income. Letting agents report income to HMRC. If your SA105 figure doesn’t match the agent’s report, expect a letter.

4. Missing the private use adjustment. If you stay in a holiday let or furnished property yourself, expenses must be apportioned. Claiming 100% of expenses on a property used partly personally flags immediately.

5. Claiming expenses from before letting began. Pre-letting expenses are only deductible if the property was genuinely being prepared for letting. Routine costs while deciding whether to let are not claimable.

6. Confusing gross and net income when using an agent. If your agent deducts their fees before paying you, your rental income is still the gross amount — the full rent before the fee. The agent fee is then claimed as a separate expense. Entering net income understates your income and overstates your deductible expenses.

7. Not declaring income from short-term lets. Airbnb and similar platforms report landlord income to HMRC. Failing to declare short-term let income on your SA105 (or SA100 trading income if it qualifies as a business) is one of HMRC’s highest-priority compliance areas.

How the SA105 Feeds Into Your Tax Bill

The taxable profit from SA105 flows into Box 17 of your SA100 (total income from property). It is added to your other income — employment, dividends, savings — and taxed at your marginal rate:

• Basic rate (20%): up to £50,270
• Higher rate (40%): £50,271 to £125,140
• Additional rate (45%): over £125,140

On top of the residential finance costs tax credit, remember to apply the £1,000 property income allowance if your gross rental income is below that threshold — in which case you don’t need to complete the SA105 at all.

If you have a complex situation — multiple properties, losses accumulated across years, or you are considering incorporation — our complete landlord guide covers the broader obligations, and the landlord tax deductions guide ensures you claim every legitimate expense before calculating the profit you report here.