Self Assessment Deadline January 2026: What You Need to Know

Last Updated: January 2026 | Tax Year: 2024-2025

The deadline is 31 January 2026.

If you need to file a Self Assessment tax return for the 2024-25 tax year, that's your final date. Miss it, and you'll face automatic penalties—no excuses accepted.

Here's everything you need to know.

Key Dates

Deadline	What's Due
~~31 October 2025~~	Paper tax return (passed)
31 January 2026	Online tax return
31 January 2026	Payment of tax owed
28 February 2026	Deadline to set up payment plan (if needed)

Already filed? Skip to Payment section.

Do You Need to File Self Assessment?

Not everyone needs to file. PAYE handles most employees' tax automatically.

You MUST File If:

Self-employed income above £1,000
Rental property income above £2,500 (or any amount if claimed expenses)
Savings or investment income above £10,000
Dividend income above £10,000
Capital gains above the annual exemption (£3,000 in 2024-25)
Foreign income that needs reporting
Income over £100,000 (even as PAYE employee)
Child Benefit clawback (High Income Child Benefit Charge)
Director of a company (even if no income)
Partner in a business partnership
Claiming tax relief on pensions, charitable donations, or expenses

You DON'T Need to File If:

PAYE-only employee earning under £100,000
No additional income sources
No tax relief claims needed
State Pension only (usually)

Unsure? HMRC's tool can help

First-Time Filer? Register Now

If you've never filed Self Assessment before, you need to register first—and this takes time.

Registration Deadlines

For the 2024-25 tax year, you should have registered by 5 October 2025. If you haven't:

Register immediately at gov.uk/register-for-self-assessment
HMRC will send your UTR (Unique Taxpayer Reference) by post
This can take up to 10 working days

No UTR yet? Call HMRC's Self Assessment helpline: 0300 200 3310

They may be able to expedite your registration if the deadline is imminent.

What Information Do You Need?

Gather these before you start:

Income Documents

P60 from each employer (shows salary and tax paid)
P45 if you changed jobs
P11D if you had benefits in kind
Self-employment records (income and expenses)
Rental income statements (and expense receipts)
Bank interest certificates (or statements showing interest)
Dividend vouchers (or company accounts)
Capital gains records (buy/sell dates, amounts)

Relief Claims

Pension contribution statements
Gift Aid donation records
Professional subscription receipts
Work expense receipts (if claiming)

Other Information

National Insurance number
UTR (Unique Taxpayer Reference)
Bank details for refund or Direct Debit

How to File Online

The easiest way for most people.

Step 1: Log Into HMRC

Go to gov.uk/log-in-file-self-assessment-tax-return

You'll need:

Government Gateway ID, or
Create one with your NI number and UTR

Can't log in? HMRC has help with account issues

Step 2: Complete Each Section

The online form walks you through:

Personal details - Address, date of birth
Employment income - P60 figures
Self-employment - Turnover, expenses, profit
Property income - Rental income and expenses
UK interest and dividends - Bank interest, share dividends
UK pensions - State pension, private pension withdrawals
Other income - Foreign income, trusts, etc.
Tax reliefs - Pensions, Gift Aid, expenses
Capital gains - If you sold assets at a profit

Tip: You can save and return later. Don't rush through—mistakes cost money.

Step 3: Review and Submit

Before submitting:

Check all figures against your documents
Review the tax calculation
Confirm your bank details

Once submitted, you'll get a submission receipt. Save this.

Common Mistakes to Avoid

1. Forgetting to Include All Income

HMRC knows about your:

Employment income (from P60/P45)
Bank interest (reported by banks)
Dividends (reported by companies)

If you don't report something and they find out, you'll face penalties.

Include everything, even if tax was already deducted.

2. Claiming Wrong Expenses

Self-employed expenses must be:

Wholly and exclusively for business
Documented with receipts
Reasonable for your business type

Personal costs (your home broadband, personal car use) need proper apportionment.

HMRC's expense guidance

3. Missing Pension Relief Claims

Higher-rate taxpayers must claim additional pension relief through Self Assessment if their pension uses "relief at source."

Your pension statement shows:

Your contribution (what you paid)
Basic rate relief added (20%)

You claim the extra 20% (or 25% for additional rate) on your return.

4. Incorrect Tax Code Assumption

The online form pre-populates some data from HMRC records. Check this carefully—it might be based on an old or incorrect tax code.

Compare against your P60 and payslips.

5. Ignoring Previous Year Payments on Account

If you made payments on account for 2024-25 (based on 2023-24's bill), these reduce what you owe now.

The online system should show these, but double-check.

Penalties for Missing the Deadline

HMRC is not forgiving.

Late Filing Penalties

When	Penalty
1 day late	£100 (automatic)
3 months late	£10 per day (max 90 days = £900)
6 months late	£300 or 5% of tax due (whichever is greater)
12 months late	£300 or 5% of tax due (additional)

Maximum late filing penalties: £1,600+ plus percentage of tax owed

Late Payment Penalties

When	Penalty
30 days late	5% of tax due
6 months late	Additional 5%
12 months late	Additional 5%

Plus: Interest on unpaid tax (currently ~7.5% annually)

Example: £5,000 Tax Bill Filed 4 Months Late

Late filing: £100 + (30 days × £10) = £400
Late payment (if unpaid 30+ days): 5% × £5,000 = £250
Total penalties: £650 (before interest)

The lesson: File on time, even if you can't pay immediately.

Can't Pay? Your Options

If you owe tax but can't afford it all at once:

1. Time to Pay Arrangement

HMRC offers payment plans for qualifying taxpayers.

Criteria:

Tax bill under £30,000
Within 60 days of deadline
No existing payment plans
Up to date with filings

Set up online at gov.uk/pay-self-assessment-tax-bill/pay-in-instalments

Or call: 0300 200 3835

2. Budget Payment Plan

For next year, you can spread payments:

Weekly or monthly Direct Debits
Based on estimated tax bill
HMRC adjusts at year-end

This avoids the lump sum shock.

3. Prioritize the Filing

Even if you can't pay, file on time.

Late filing penalty: £100+ (automatic)
Late payment penalty: 5% (after 30 days)

Filing on time and paying late is better than both being late.

Paying Your Tax Bill

Payment Methods

Method	Time to Clear
Online banking (Faster Payments)	Same or next day
Debit card online	Immediate
Direct Debit	3-5 working days
BACS	3 working days
CHAPS	Same day
Cheque	Allow 5+ working days

Recommended: Online banking or debit card—fastest and confirmed.

Payment Reference

You'll need your UTR followed by 'K' (e.g., 1234567890K).

Find your UTR:

Previous tax returns
HMRC correspondence
Your Personal Tax Account

Payments on Account

If your bill is over £1,000 (and tax wasn't mostly collected via PAYE), HMRC requires payments on account for next year:

31 January 2026: 50% of estimated 2025-26 tax
31 July 2026: Another 50%

This means you might pay:

2024-25 tax owed
First payment on account for 2025-26

Total due 31 January could be 150% of your tax bill.

Last-Minute Filing Tips

Got Days Left?

Gather documents now - P60, bank statements, invoices
Log into HMRC tonight - Check your details are correct
Start filling in - You can save progress
Don't wait until 31st - Servers get slow

Got Hours Left?

Use estimates if needed - You can amend later (within 12 months)
File, even if incomplete - Penalty for late > penalty for amendment
Screenshot your submission - Proof you filed on time

Filing After Midnight?

HMRC's system accepts returns up to midnight on 31 January.

But if there are technical issues, you might not get sympathy. Don't cut it that close.

After You File

Keep Records

Maintain tax records for at least 5 years (6 years for self-employed).

HMRC can enquire into your return for up to 4 years (longer if they suspect fraud).

Set Calendar Reminders

For next year:

October: Register if first time
November-December: Gather documents
Early January: File return
31 January: Payment due

Review Your Tax Calculation

HMRC's online system shows how they calculated your tax. Review this for:

Correct allowances applied
All income properly taxed
Expected reliefs included

If something looks wrong, you can amend within 12 months.

Frequently Asked Questions

What is the Self Assessment deadline for 2024-25?

The online Self Assessment deadline for the 2024-25 tax year is 31 January 2026. Paper returns were due 31 October 2025.

What happens if I miss the 31 January deadline?

You'll receive an automatic £100 penalty, even if you owe no tax. Additional penalties apply after 3 months (£10/day), 6 months, and 12 months. Interest accrues on unpaid tax.

Can I file after 31 January?

Yes, but you'll face penalties. File as soon as possible to minimize them. The £10/day penalty only kicks in after 3 months, so filing in February is better than waiting.

How do I pay my Self Assessment tax bill?

Online banking (Faster Payments) is fastest—same or next day. You can also pay by debit card online or set up a Direct Debit. Your payment reference is your UTR followed by 'K'.

Can I get an extension on the deadline?

HMRC rarely grants extensions. COVID-era flexibility is over. If you have a "reasonable excuse" (serious illness, bereavement, HMRC system failure), you may appeal penalties, but you must still file ASAP.

Do I need to file if I only have PAYE income?

Most PAYE-only employees don't need to file. However, you must file if you earn over £100,000, claim tax relief not handled by your employer, or have untaxed income above £2,500.

Key Takeaways

Deadline is 31 January 2026 for online returns
File on time even if you can't pay—late filing penalties are worse
Gather documents early - P60, bank statements, expense receipts
Check your calculation after filing for errors
Set up a payment plan if you can't pay in full (apply by end of February)
Keep records for 5-6 years in case of HMRC enquiry

Need Help Calculating Your Tax?

Use our free calculator to estimate your Self Assessment bill:

Calculate your tax now

Last Updated: January 2026 | Tax Year: 2024-2025

The deadline is 31 January 2026.

If you need to file a Self Assessment tax return for the 2024-25 tax year, that's your final date. Miss it, and you'll face automatic penalties—no excuses accepted.

Here's everything you need to know.

Key Dates

Deadline	What's Due
~~31 October 2025~~	Paper tax return (passed)
31 January 2026	Online tax return
31 January 2026	Payment of tax owed
28 February 2026	Deadline to set up payment plan (if needed)

Already filed? Skip to Payment section.

Do You Need to File Self Assessment?

Not everyone needs to file. PAYE handles most employees' tax automatically.

You MUST File If:

Self-employed income above £1,000
Rental property income above £2,500 (or any amount if claimed expenses)
Savings or investment income above £10,000
Dividend income above £10,000
Capital gains above the annual exemption (£3,000 in 2024-25)
Foreign income that needs reporting
Income over £100,000 (even as PAYE employee)
Child Benefit clawback (High Income Child Benefit Charge)
Director of a company (even if no income)
Partner in a business partnership
Claiming tax relief on pensions, charitable donations, or expenses

You DON'T Need to File If:

PAYE-only employee earning under £100,000
No additional income sources
No tax relief claims needed
State Pension only (usually)

Unsure? HMRC's tool can help

First-Time Filer? Register Now

If you've never filed Self Assessment before, you need to register first—and this takes time.

Registration Deadlines

For the 2024-25 tax year, you should have registered by 5 October 2025. If you haven't:

Register immediately at gov.uk/register-for-self-assessment
HMRC will send your UTR (Unique Taxpayer Reference) by post
This can take up to 10 working days

No UTR yet? Call HMRC's Self Assessment helpline: 0300 200 3310

They may be able to expedite your registration if the deadline is imminent.

What Information Do You Need?

Gather these before you start:

Income Documents

P60 from each employer (shows salary and tax paid)
P45 if you changed jobs
P11D if you had benefits in kind
Self-employment records (income and expenses)
Rental income statements (and expense receipts)
Bank interest certificates (or statements showing interest)
Dividend vouchers (or company accounts)
Capital gains records (buy/sell dates, amounts)

Relief Claims

Pension contribution statements
Gift Aid donation records
Professional subscription receipts
Work expense receipts (if claiming)

Other Information

National Insurance number
UTR (Unique Taxpayer Reference)
Bank details for refund or Direct Debit

How to File Online

The easiest way for most people.

Step 1: Log Into HMRC

Go to gov.uk/log-in-file-self-assessment-tax-return

You'll need:

Government Gateway ID, or
Create one with your NI number and UTR

Can't log in? HMRC has help with account issues

Step 2: Complete Each Section

The online form walks you through:

Personal details - Address, date of birth
Employment income - P60 figures
Self-employment - Turnover, expenses, profit
Property income - Rental income and expenses
UK interest and dividends - Bank interest, share dividends
UK pensions - State pension, private pension withdrawals
Other income - Foreign income, trusts, etc.
Tax reliefs - Pensions, Gift Aid, expenses
Capital gains - If you sold assets at a profit

Tip: You can save and return later. Don't rush through—mistakes cost money.

Step 3: Review and Submit

Before submitting:

Check all figures against your documents
Review the tax calculation
Confirm your bank details

Once submitted, you'll get a submission receipt. Save this.

Common Mistakes to Avoid

1. Forgetting to Include All Income

HMRC knows about your:

Employment income (from P60/P45)
Bank interest (reported by banks)
Dividends (reported by companies)

If you don't report something and they find out, you'll face penalties.

Include everything, even if tax was already deducted.

2. Claiming Wrong Expenses

Self-employed expenses must be:

Wholly and exclusively for business
Documented with receipts
Reasonable for your business type

Personal costs (your home broadband, personal car use) need proper apportionment.

HMRC's expense guidance

3. Missing Pension Relief Claims

Higher-rate taxpayers must claim additional pension relief through Self Assessment if their pension uses "relief at source."

Your pension statement shows:

Your contribution (what you paid)
Basic rate relief added (20%)

You claim the extra 20% (or 25% for additional rate) on your return.

4. Incorrect Tax Code Assumption

The online form pre-populates some data from HMRC records. Check this carefully—it might be based on an old or incorrect tax code.

Compare against your P60 and payslips.

5. Ignoring Previous Year Payments on Account

If you made payments on account for 2024-25 (based on 2023-24's bill), these reduce what you owe now.

The online system should show these, but double-check.

Penalties for Missing the Deadline

HMRC is not forgiving.

Late Filing Penalties

When	Penalty
1 day late	£100 (automatic)
3 months late	£10 per day (max 90 days = £900)
6 months late	£300 or 5% of tax due (whichever is greater)
12 months late	£300 or 5% of tax due (additional)

Maximum late filing penalties: £1,600+ plus percentage of tax owed

Late Payment Penalties

When	Penalty
30 days late	5% of tax due
6 months late	Additional 5%
12 months late	Additional 5%

Plus: Interest on unpaid tax (currently ~7.5% annually)

Example: £5,000 Tax Bill Filed 4 Months Late

Late filing: £100 + (30 days × £10) = £400
Late payment (if unpaid 30+ days): 5% × £5,000 = £250
Total penalties: £650 (before interest)

The lesson: File on time, even if you can't pay immediately.

Can't Pay? Your Options

If you owe tax but can't afford it all at once:

1. Time to Pay Arrangement

HMRC offers payment plans for qualifying taxpayers.

Criteria:

Tax bill under £30,000
Within 60 days of deadline
No existing payment plans
Up to date with filings

Set up online at gov.uk/pay-self-assessment-tax-bill/pay-in-instalments

Or call: 0300 200 3835

2. Budget Payment Plan

For next year, you can spread payments:

Weekly or monthly Direct Debits
Based on estimated tax bill
HMRC adjusts at year-end

This avoids the lump sum shock.

3. Prioritize the Filing

Even if you can't pay, file on time.

Late filing penalty: £100+ (automatic)
Late payment penalty: 5% (after 30 days)

Filing on time and paying late is better than both being late.

Paying Your Tax Bill

Payment Methods

Method	Time to Clear
Online banking (Faster Payments)	Same or next day
Debit card online	Immediate
Direct Debit	3-5 working days
BACS	3 working days
CHAPS	Same day
Cheque	Allow 5+ working days

Recommended: Online banking or debit card—fastest and confirmed.

Payment Reference

You'll need your UTR followed by 'K' (e.g., 1234567890K).

Find your UTR:

Previous tax returns
HMRC correspondence
Your Personal Tax Account

Payments on Account

If your bill is over £1,000 (and tax wasn't mostly collected via PAYE), HMRC requires payments on account for next year:

31 January 2026: 50% of estimated 2025-26 tax
31 July 2026: Another 50%

This means you might pay:

2024-25 tax owed
First payment on account for 2025-26

Total due 31 January could be 150% of your tax bill.

Last-Minute Filing Tips

Got Days Left?

Gather documents now - P60, bank statements, invoices
Log into HMRC tonight - Check your details are correct
Start filling in - You can save progress
Don't wait until 31st - Servers get slow

Got Hours Left?

Use estimates if needed - You can amend later (within 12 months)
File, even if incomplete - Penalty for late > penalty for amendment
Screenshot your submission - Proof you filed on time

Filing After Midnight?

HMRC's system accepts returns up to midnight on 31 January.

But if there are technical issues, you might not get sympathy. Don't cut it that close.

After You File

Keep Records

Maintain tax records for at least 5 years (6 years for self-employed).

HMRC can enquire into your return for up to 4 years (longer if they suspect fraud).

Set Calendar Reminders

For next year:

October: Register if first time
November-December: Gather documents
Early January: File return
31 January: Payment due

Review Your Tax Calculation

HMRC's online system shows how they calculated your tax. Review this for:

Correct allowances applied
All income properly taxed
Expected reliefs included

If something looks wrong, you can amend within 12 months.

Frequently Asked Questions

What is the Self Assessment deadline for 2024-25?

The online Self Assessment deadline for the 2024-25 tax year is 31 January 2026. Paper returns were due 31 October 2025.

What happens if I miss the 31 January deadline?

You'll receive an automatic £100 penalty, even if you owe no tax. Additional penalties apply after 3 months (£10/day), 6 months, and 12 months. Interest accrues on unpaid tax.

Can I file after 31 January?

Yes, but you'll face penalties. File as soon as possible to minimize them. The £10/day penalty only kicks in after 3 months, so filing in February is better than waiting.

How do I pay my Self Assessment tax bill?

Online banking (Faster Payments) is fastest—same or next day. You can also pay by debit card online or set up a Direct Debit. Your payment reference is your UTR followed by 'K'.

Can I get an extension on the deadline?

Do I need to file if I only have PAYE income?

Most PAYE-only employees don't need to file. However, you must file if you earn over £100,000, claim tax relief not handled by your employer, or have untaxed income above £2,500.

Key Takeaways

Deadline is 31 January 2026 for online returns
File on time even if you can't pay—late filing penalties are worse
Gather documents early - P60, bank statements, expense receipts
Check your calculation after filing for errors
Set up a payment plan if you can't pay in full (apply by end of February)
Keep records for 5-6 years in case of HMRC enquiry

Need Help Calculating Your Tax?

Use our free calculator to estimate your Self Assessment bill:

Calculate your tax now

Key Dates

Do You Need to File Self Assessment?

You MUST File If:

You DON'T Need to File If:

First-Time Filer? Register Now

Registration Deadlines

What Information Do You Need?

Income Documents

Relief Claims

Other Information

How to File Online

Step 1: Log Into HMRC

Step 2: Complete Each Section

Step 3: Review and Submit

Common Mistakes to Avoid

1. Forgetting to Include All Income

2. Claiming Wrong Expenses

3. Missing Pension Relief Claims

4. Incorrect Tax Code Assumption

5. Ignoring Previous Year Payments on Account

Penalties for Missing the Deadline

Late Filing Penalties

Late Payment Penalties

Example: £5,000 Tax Bill Filed 4 Months Late

Can't Pay? Your Options

1. Time to Pay Arrangement

2. Budget Payment Plan

3. Prioritize the Filing

Paying Your Tax Bill

Payment Methods

Payment Reference

Payments on Account

Last-Minute Filing Tips

Got Days Left?

Got Hours Left?

Filing After Midnight?

After You File

Keep Records

Set Calendar Reminders

Review Your Tax Calculation

Frequently Asked Questions

What is the Self Assessment deadline for 2024-25?

What happens if I miss the 31 January deadline?

Can I file after 31 January?

How do I pay my Self Assessment tax bill?

Can I get an extension on the deadline?

Do I need to file if I only have PAYE income?

Key Takeaways

Need Help Calculating Your Tax?

Related Guides

Found this helpful?

Related Articles

Understanding the UK Tax System: Complete Guide 2025

Key Dates

Do You Need to File Self Assessment?

You MUST File If:

You DON'T Need to File If:

First-Time Filer? Register Now

Registration Deadlines

What Information Do You Need?

Income Documents

Relief Claims

Other Information

How to File Online

Step 1: Log Into HMRC

Step 2: Complete Each Section

Step 3: Review and Submit

Common Mistakes to Avoid

1. Forgetting to Include All Income

2. Claiming Wrong Expenses

3. Missing Pension Relief Claims

4. Incorrect Tax Code Assumption

5. Ignoring Previous Year Payments on Account

Penalties for Missing the Deadline

Late Filing Penalties

Late Payment Penalties

Example: £5,000 Tax Bill Filed 4 Months Late

Can't Pay? Your Options

1. Time to Pay Arrangement

2. Budget Payment Plan