Who needs to file a Self Assessment?

• Self-employed / sole trader with trading income above the trading allowance (or you want to claim actual expenses).
• Partner in a partnership (the partnership files an SA800; each partner files an SA100).
• Landlord with UK property income (including holiday lets/Airbnb).
• You need to report Capital Gains Tax (e.g., shares, crypto, second property, reported via SA108).
• High earner who owes the High Income Child Benefit Charge.
• You received untaxed income (dividends, bank interest, tips/commission, foreign income).
• HMRC sent you a notice to file (you must file even if you think you owe nothing).

Unsure? Work through the sections below or start your return in Ftax, we’ll switch on only the pages you need.

• Sole traders and freelancers generally file an SA100 plus SA103 (self-employment pages). If you keep records and claim expenses (home working, mileage, equipment), Self Assessment is how you do it.
• Partnerships file a partnership return (SA800) for the business and each partner files their own SA100, reporting their share of profits/losses.
• If your side-hustle is small and within the trading allowance, you might not need a full return, but once you exceed it (or want to claim expenses), you should register and file.

Helpful next steps:
See Self Assessment for sole traders or start the SA100 in Ftax and we’ll add SA103 automatically.

• Rent from a UK property (including a room in your home, Airbnb/holiday lets, or a jointly owned property) is property income. Most landlords file SA100 + SA105.
• Some small amounts can be covered by the property allowance; otherwise you’ll claim allowable expenses (repairs, agent fees, insurance, finance costs subject to rules).
• Selling a property may also trigger Capital Gains reporting (see below).

Helpful next steps:
See Self Assessment for landlords or start your SA100 and we’ll activate SA105 where needed.

• If you or your partner received Child Benefit and your income is high enough to trigger the High Income Child Benefit Charge, you normally need to file.
• Pension contributions and Gift Aid: if you pay higher-rate tax, Self Assessment is how you claim the extra relief above basic rate.
• Benefits-in-kind or other untaxed benefits may also create a need to file, depending on how your employer processes them.

Helpful next steps:
Use the Ftax SA100 to enter salary, benefits and reliefs; we’ll calculate the impact and show what’s due.

• Disposals of shares, funds, crypto or property that isn’t your main home can trigger Capital Gains Tax reporting via SA108.
• Even where gains are within the annual allowance, certain disposals or total proceeds may still require reporting. Keep detailed records of purchase/sale dates, costs and fees.

• Overseas interest/dividends, foreign rental income, or remittances usually need SA106.
• Non-resident or split-year cases can be more complex; you may still need a UK return if you have UK-source income or gains.
• Trustees/estates typically use SA900 (see our Trusts & Estates hub), but individual beneficiaries might also need SA100 entries.

• Being a director isn’t an automatic trigger, but many directors file because they receive dividends or have untaxed income/benefits.
• If HMRC issues a notice to file, you must complete a return unless they agree in writing to withdraw it.

You might not need a full SA100 if:

• All income is taxed through PAYE, you have no untaxed income, and you’re not claiming reliefs that require Self Assessment.
• Small casual earnings are within the trading allowance and you don’t want to claim expenses.
• Small property income is within the property allowance and you don’t need to claim expenses.

HMRC has confirmed (in writing) that a return isn’t required for the year.
Already received a notice to file but believe it isn’t needed? Ask HMRC to withdraw the return, only HMRC can confirm this.