Self Assessment quick compliance check

Use this checklist to confirm you are on track with your Self Assessment obligations for the current tax year.

Key deadlines

Filing and payment deadlines

Confirm you know when your return is due and when payment must reach HMRC.

Register for Self Assessment: 5 October after the tax year ends
Paper return deadline: 31 October after the tax year ends (11:59pm)
Online return deadline: 31 January after the tax year ends (11:59pm)
Earliest submission date: 6 April, the day after the tax year ends
Pay through your tax code: File online by 30 December (bills under £3,000)
Amendment window: 12 months from the filing deadline

HMRC must receive a paper return by the deadline; posting it in time is not enough. If you register after 5 October, HMRC gives you a later deadline of 3 months from the date of its letter or email, but you must still pay by 31 January.

Payment deadlines and payments on account

Check whether you need to make payments on account in addition to your balancing payment.

Main payment deadline: 31 January following the tax year end
First payment on account: 31 January (during tax year)
Second payment on account: 31 July (after tax year ends)
Balancing payment: 31 January (if actual liability exceeds payments on account)

Filing your return

Confirm your return is filed or on track. Filing early gives you more time to arrange payment.

File your Self Assessment tax return

Deadlines, supplementary pages, and step-by-step filing process.

Payment

Confirm your payment method and allow enough processing time before the deadline.

Pay your Self Assessment tax bill

Payment methods, processing times, and options if you cannot pay in full.

Penalty risks

Check that you are not at risk of penalties for late filing or late payment.

Avoid Self Assessment penalties

Penalty escalation, interest rates, and how to appeal if penalised.

Late filing penalties

Penalties start at a fixed charge and escalate the longer you delay.

1 day late: £100 fixed penalty (applies even if no tax owed)
3 months late: £10 per day (up to 90 days = £900 maximum)
6 months late: 5% of tax owed or £300, whichever is higher
12 months late: Additional 5% of tax owed or £300, whichever is higher
Maximum penalty: Up to 100% of tax owed in serious cases

Penalties are cumulative. Filing 12 months late can result in £100 + £900 + two 5% penalties. Partnership returns incur penalties for all partners if late.

Making Tax Digital readiness

Check whether MTD for Income Tax applies to you.

Prepare for Making Tax Digital

Phased rollout thresholds, software requirements, and quarterly deadlines.

MTD for Income Tax thresholds

MTD for Income Tax applies from 6 April 2026 to sole traders and landlords with qualifying income over £50,000, with lower thresholds from 2027 and 2028.

From 6 April 2026: Qualifying income over £50,000 in 2024-25
From 6 April 2027: Qualifying income over £30,000 in 2025-26
From 6 April 2028: Qualifying income over £20,000 in 2026-27
Qualifying income: Self-employment and property income before expenses
Who the thresholds apply to: Sole traders and landlords
Exemptions: Exemptions apply, for example if you are digitally excluded
Partners: Partnership income alone does not bring you in
Partnerships: Not yet in MTD; timetable to be set

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Self Assessment quick compliance check