UK Tax Deadlines and Requirements [2025/26]

The 2025/2026 tax year has officially begun! The UK’s tax season runs from 6 April the current year to April 5 the next. It’s the tax year to report and file your 2024/25 incomes. Be sure to know all the key tax deadlines and requirements throughout the tax season so you can have the upper hand over your tax and finances.

Table of Contents

• UK Tax Deadlines and Requirements for Self-Assessment [2025/26]
• Payment and UK Tax Filing Dates for Limited Companies
• Tax Deadlines and Requirements for Employers
• Should You Register for Making Tax Digital Now?
• FAQs
• Get Tax Advice

UK Tax Deadlines and Requirements for Self-Assessment [2025/26]?

Keep these responsibilities and key dates in mind:

• 31 July 2025 – second payment on account for the 2024/25 tax year
• 5 October 2025 – last day you can register for self-assessment for the 2024/25 tax year

Meanwhile, there are various self-assessment filing dates UK according to your filing method and purpose:

• 31 October 2025 – deadline to submit your paper self-assessments for the 2024/25 tax year
• 30 December 2025 – deadline to file online self-assessments to pay your 2024/25 tax bill through your PAYE tax code
• 31 January 2026 – deadline to file your online tax return for the 2024/25 tax year

For 2026, your responsibilities from the 2024/25 tax year continue:

• 31 January 2026 – income tax due date UK for your 2024/25 tax bill

5 April 2026 marks the end of the 2025/26 tax year. Your major responsibility is filing your self-assessments (highly recommended to do so online), but you still have nine months for that.

Payment and UK Tax Filing Dates for Limited Companies

Limited companies, on the other hand, do not file self-assessments but corporation tax returns. Here’s when to file UK taxes if you are a UK company:

• Annual Accounts to Companies House – 9 months after your company’s financial year ends
• Corporate Tax Deadline UK – 9 months and 1 day after your company’s financial year ends
• CT600 Company Tax Return – 12 months after your company’s year-end
• Confirmation Statement to Companies House – 12 months after company setup (or last confirmation statement date)
• Dormant Accounts – 9 months after your company’s financial year ends (for companies not actively trading)

VAT deadline UK for registration is not definite. Once you exceed the annual VAT registration threshold (£90,000), you need to register within 30 days.

If you are not sure about your tax and legal obligations, a trusted corporate tax accountant offers  crucial help.

Should You Register for Making Tax Digital Now?

Some people will need to use Making Tax Digital for Income Tax starting 6 April 2026. See if you also need to register for MTD for ITSA:

• You are registered for Self Assessment.
• You receive income from self-employment or property (or both) prior to 6 April 2025.
• Your qualifying income for the 2024 to 2025 tax year is more than £50,000.

If all of the above applies, be sure to register as early as this year.

FAQs

What forms do I need to fill out for self-assessment?

You will generally need to fill out the SA100 form—this is the main tax return form for self-assessment. Additional supplementary pages may be needed based on your income sources.

Can I amend my tax return if I make a mistake?

Yes, if you realise that you have made an error after submission, you can amend your tax return for up to 12 months after the filing deadline.

What if I am unable to pay my tax bill on time?

If you cannot pay your tax bill by the due date, contact HMRC as soon as possible to discuss your options, which may include payment plans.

Do I need to file a self-assessment if I am employed?

Not necessarily. If your only income is from employment and tax is deducted at source, you might not need to file. However, if you have additional income, you will likely need to submit a self-assessment.

What are payments on account?

Payments on account are advance payments towards your next year’s tax bill, for self-employed individuals or those with other untaxed income. They are due by 31 January and 31 July.

Get Tax Advice

Keeping the key UK tax deadlines and requirements in mind will help you avoid any penalties and interest for any late filing or payment. If you’re searching for a tax specialist near me to clarify your self-assessment responsibilities or to better strategise your tax and financial position this year, Legend Financial is here to assist you.