When to Report Additional Income to HMRC: 2025/26 Rules for Online Sellers and Renters

What the source announced

The 2025 to 2026 UK tax year runs from 6 April 2025 to 5 April 2026. Gov.uk provides an online tool that checks whether a Self Assessment tax return is required for income falling within this period (gov.uk, Self Assessment).

Taxpayers with income beyond their primary source should check whether they need to tell HMRC. Gov.uk identifies selling things online and renting out part of your home as examples of additional income that may trigger this reporting check (gov.uk, Self Assessment).

The gov.uk guidance frames the additional income obligation conditionally, 'check if you need to tell HMRC', rather than as a blanket requirement. Selling things online and renting out part of your home are the two examples the guidance provides (gov.uk, Self Assessment).

What this means for your income tax

The 2025 to 2026 tax year runs from 6 April 2025 to 5 April 2026. A rental receipt or completed online sale occurring before 5 April 2026 sits within the 2025/26 return; the same type of income received from 6 April 2026 falls into the following tax year.

The gov.uk guidance directs those with additional income, such as selling things online or renting out part of a home, to check if they need to tell HMRC. The check gov.uk advises is the step that establishes whether the obligation applies to a given taxpayer's position.

Use the income tax calculator → to see how income from online selling or property rental sits alongside other earnings when working out your total income tax position for the year.

Where the £1,000 allowances set the reporting line

The 'check if you need to tell HMRC' framing has a concrete floor. You can get up to £1,000 each tax year in tax-free allowances for property or trading income (gov.uk) — the trading allowance covers income from self-employment or casual services, and the property allowance covers income from land or property. If your annual gross property income is £1,000 or less, from one or more property businesses, you will not have to tell HMRC or declare this income on a tax return (gov.uk).

Above the floor, gov.uk publishes a notification ladder. Gross trading income over £1,000 means registering for Self Assessment; gross property income over £1,000 up to £2,500 means contacting HMRC, and property income over £2,500 means registering for Self Assessment (gov.uk). If you have both types of income, you get a £1,000 allowance for each (gov.uk). The full mechanics — including the choice between the allowance and deducting actual expenses, and the Rent a Room Scheme boundary — are set out in the trading and property allowances guide.

Worked example: online selling beside a £28,000 salary

An employee earns £28,000 in 2025/26 and sells items online for £1,800 gross across the year. The 2025/26 bands charge 20% on taxable income between £12,571 and £50,270 after the £12,570 Personal Allowance (gov.uk).

• Step 1: Gross trading income is £1,800 — over £1,000, so Self Assessment registration is required under the gov.uk ladder.
• Step 2: The trading allowance removes the first £1,000: £1,800 − £1,000 = £800 taxable.
• Step 3: Salary of £28,000 sits inside the basic-rate band, and £28,000 + £800 = £28,800 stays well below £50,270, so the £800 is charged at 20%: £800 × 20% = £160.

Selling £1,800 of goods produces a £160 tax bill and a return to file — the return is triggered by the £1,000 line, not by the size of the bill.

Worked example: both allowances, nothing to report

A different taxpayer earns £950 from casual gardening work and £900 from letting out a driveway in the same tax year. Trading and property are separate £1,000 allowances (gov.uk), so each income stream is tested against its own limit:

• Trading income: £950 ≤ £1,000 — inside the trading allowance.
• Property income: £900 ≤ £1,000 — inside the property allowance, and below the level at which gov.uk says HMRC must be told.

Total additional income of £1,850 generates no tax and no reporting obligation. The same £1,850 earned entirely from one activity would cross that activity's £1,000 line and trigger the ladder — the split matters as much as the total. One caveat from the gov.uk rules: the property allowance cannot be used on income from letting a room in your own home under the Rent a Room Scheme (gov.uk), so a lodger's rent follows a different route from a driveway or parking space.

Worked example: rental income beside a £59,000 salary — tax plus the Child Benefit charge

Additional income can trigger more than income tax. Take a parent claiming Child Benefit, earning £59,000, who lets a parking space for £2,400 gross in 2025/26:

• Step 1: Property allowance: £2,400 − £1,000 = £1,400 taxable.
• Step 2: The salary already sits above the £50,270 higher-rate threshold (gov.uk), so the £1,400 slice is charged at 40%: £1,400 × 40% = £560.
• Step 3: Reporting: £2,400 of gross property income falls in the over-£1,000-up-to-£2,500 rung, which means contacting HMRC rather than a full return (gov.uk).
• Step 4: Adjusted net income becomes £59,000 + £1,400 = £60,400 — £400 over the £60,000 threshold at which the High Income Child Benefit Charge starts for tax years from 2024/25 (gov.uk). The charge claws back 1% of Child Benefit for every £200 over the threshold (gov.uk): £400 ÷ £200 = 2, so 2% of the year's Child Benefit is repayable on top of the £560.

Without the rental income, adjusted net income of £59,000 sits under the threshold and no charge applies. The extra £2,400 gross switches on a second, separate liability.

The £50,270 knock-on: your savings allowance halves

Crossing into the higher-rate band changes the tax on savings interest as well as the rate on the additional income itself. The Personal Savings Allowance is £1,000 for basic-rate taxpayers and £500 for higher-rate taxpayers (gov.uk).

A £49,800 salary plus £900 of taxable rental income makes £50,700 — £430 over the £50,270 threshold (gov.uk). The income tax on the rental slice is modest: £470 at 20% (£94) plus £430 at 40% (£172) = £266. The quieter effect is on the Personal Savings Allowance, which drops from £1,000 to £500 because the taxpayer is now in the higher-rate band — any savings interest between £500 and £1,000 that was previously tax-free becomes taxable. A few hundred pounds of side income can change the tax treatment of an unrelated savings account.

Running your own numbers

Each example above follows the same sequence: gross additional income, minus any allowance, stacked on top of existing earnings, taxed at the rate of the band the combined total lands in. Calculate Your Take-Home Pay → with and without the additional income — the difference between the two results is the tax cost of the side income, and the gov.uk ladder above tells you whether HMRC needs to hear about it.