The 2025/26 tax year runs from 6 April 2025 to 5 April 2026. Your online Self Assessment tax return for this year must be submitted to HMRC by 31 January 2027, and any tax you owe must be paid by the same date.
This guide is a practical checklist: who needs to file, what you need to gather, the key deadlines, and what happens if you miss them.
Do you need to file a Self Assessment return for 2025/26?
Not everyone needs to file. HMRC requires a Self Assessment tax return if, during the 2025/26 tax year, any of the following applied to you:
- You were self-employed as a sole trader with gross income above £1,000
- You were a partner in a business partnership
- You had gross property income above £1,000 that you are required to report through Self Assessment (if your gross property income is between £1,000 and £2,500, contact HMRC — they will tell you how to report it; if it is above £2,500, you must register for Self Assessment)
- You or your partner received Child Benefit and either of you had adjusted net income above £60,000 (the High Income Child Benefit Charge). The charge is 1% of your Child Benefit for every £200 of income above £60,000, up to the full amount at £80,000. Note: from September 2025, HMRC launched a PAYE digital service that allows some claimants to pay the HICBC through their tax code rather than through Self Assessment. If you are paying the charge through PAYE, you may not need to file a return for this reason alone
- You had untaxed income of £2,500 or more — for example from tips, commission, or savings
- You received income from abroad that you need to pay tax on
- You had capital gains above the annual exempt amount (£3,000 for 2025/26)
- You were a company director who received dividends, other untaxed income, or taxable benefits — not all directors are required to file, but many will need to depending on their circumstances
- Your state pension was your only income and it exceeded the Personal Allowance — in most cases, HMRC will collect any tax owed by sending you a Simple Assessment rather than requiring a Self Assessment return. Self Assessment may still be needed if you have other reportable income or meet another filing trigger
- You received a notice from HMRC asking you to file a return
If you are unsure, HMRC provides a free online checker tool at Gov.uk.
Important: if HMRC has issued you a notice to file a return, you must complete it even if you believe you owe no tax. Failing to submit a return that HMRC has requested will trigger automatic penalties.
Key deadlines for the 2025/26 tax year
| Date | Action |
|---|
| 5 April 2026 | End of the 2025/26 tax year |
| 5 October 2026 | Deadline to register for Self Assessment if you have not filed before |
| 31 October 2026 | Deadline to submit a paper tax return |
| 30 December 2026 | Deadline to submit online if you want to pay through your PAYE tax code |
| 31 January 2027 | Deadline to submit your online return AND pay any tax owed |
| 31 January 2027 | First payment on account for 2026/27 also due (if applicable) |
| 31 July 2027 | Second payment on account for 2026/27 due (if applicable) |
If you register for Self Assessment after 5 October 2026 and HMRC sends you a notice to file, you will have three months from the date on that letter to submit — but interest on any tax owed still runs from 31 January 2027.
Step 1: Make sure you are registered
If you filed a Self Assessment return last year, you are already registered. Your Unique Taxpayer Reference (UTR) remains the same.
If this is your first time filing, you must register with HMRC at Gov.uk. After registering, HMRC will post you a UTR, which typically takes up to 15 working days. You will also need an activation code for HMRC's online services, which arrives separately within approximately 10 days and is valid for 28 days.
Do not leave registration to the last minute. If you register in January 2027, you will almost certainly miss the filing deadline while waiting for your UTR and activation code.
Step 2: Gather your income records
Before you sit down to fill in your return, gather all documentation for every source of income you received during the 2025/26 tax year:
Employment income
- P60 from each employer (total pay and tax deducted for the year)
- P45 from any jobs you left during the year
- P11D or P11D(b) if you received taxable benefits in kind (company car, health insurance, etc.)
Self-employment income
- Complete records of all business income received
- All invoices issued during the year
- Bank statements for your business account
Property income
- Rental income records or letting agent statements
- Details of any short-term holiday letting income (note: the separate furnished holiday lettings tax regime was abolished from 6 April 2025 — this income is now treated as part of your normal UK or overseas property business under the same rules as other rental income)
Savings and investments
- Interest certificates from banks and building societies (or check your annual summary online)
- Dividend vouchers or statements from shareholdings
- Capital gains records for any assets sold (shares, property, cryptocurrency, etc.)
Pensions and other income
- State pension payment records
- Private or workplace pension statements
- Any lump sums taken from pensions
- Foreign income records and evidence of foreign tax paid
- Trusts and estates — SA107 if you received income from these
- Any other untaxed income (tips, freelance work, casual earnings)
Track your 2025/26 income and expenses in one place
Our Self Assessment 2025/26 Tracker has income logs, expense categories, quarterly summaries, and a submission-ready pack — all pre-set for the correct tax year.
View SA 2025/26 Tracker — £4.99
Step 3: Gather your expense and deduction records
If you are self-employed, you need records of all allowable business expenses. HMRC's "wholly and exclusively" rule applies: an expense is allowable only if it was incurred entirely for the purpose of your trade. If it has a dual business and personal purpose, you must apportion it.
Common allowable expenses for sole traders
- Office costs (stationery, phone bills, postage)
- Travel costs (fuel, train fares, parking — not ordinary commuting)
- Staff costs (wages, subcontractors, employer NI)
- Stock and materials
- Financial costs (insurance, bank charges, accountancy fees)
- Premises costs (rent, rates, utilities for business premises)
- Advertising and marketing
- Professional subscriptions
- Training courses directly related to your current trade
- Simplified expenses for working from home: HMRC's flat-rate scale for self-employed people is based on hours worked from home per month — £10 per month for 25 to 50 hours, £18 per month for 51 to 100 hours, and £26 per month for 101 hours or more. No receipts are needed for these flat rates
- Simplified mileage expenses (45p per mile for the first 10,000 miles, 25p per mile thereafter)
For property landlords
- Mortgage interest (20% tax credit only, not deducted from income — Section 24)
- Letting agent fees
- Insurance premiums
- Repairs and maintenance (not improvements)
- Ground rent and service charges
- Council tax (if paid by you, not the tenant)
Deductions available to everyone
- Pension contributions: if your workplace pension uses a net pay arrangement, full tax relief is given automatically through payroll and you do not normally need to claim through Self Assessment. If your pension uses relief at source, basic-rate (20%) relief is added automatically, but higher-rate and additional-rate taxpayers need to claim the extra relief through Self Assessment or by contacting HMRC
- Gift Aid donations
- Blind Person's Allowance (£3,130 for 2025/26)
- Marriage Allowance transfer (up to £1,260 to a spouse or civil partner)
Record-keeping requirements: HMRC requires self-employed individuals and landlords to retain business records for at least five years after the 31 January submission deadline. For 2025/26, this means keeping business records until at least 31 January 2032. If you are not self-employed and file for other reasons (such as employment or investment income only), keep records for at least 22 months after the end of the tax year — until at least January 2028.
Step 4: Know your tax rates for 2025/26
Income Tax (England, Wales, Northern Ireland)
| Band | Taxable income | Rate |
|---|
| Personal Allowance | Up to £12,570 | 0% |
| Basic rate | £12,571 – £50,270 | 20% |
| Higher rate | £50,271 – £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
The Personal Allowance reduces by £1 for every £2 of income above £100,000, and is completely removed at £125,140. Scottish taxpayers have separate rate bands — check Gov.uk.
National Insurance for the self-employed
| Class | Rate | Notes |
|---|
| Class 4 | 6% on £12,570–£50,270; 2% above | Paid through Self Assessment |
| Class 2 | Voluntary: £3.50/week (£182/year) | Auto-credited if profits above £6,845 |
From 2024/25 onwards, Class 2 NI is no longer compulsory. If your profits exceed £6,845, HMRC automatically credits your National Insurance record for State Pension purposes at no cost. Below this threshold, you may wish to pay voluntarily.
Other rates
- Dividend allowance: £500 tax-free. Basic rate 8.75%, higher 33.75%, additional 39.35%
- Capital Gains Tax: £3,000 annual exempt amount. Basic rate 18%, higher rate 24% — applies to all chargeable assets including shares, property, and other gains. The previous lower rates of 10%/20% for non-residential assets were replaced from 30 October 2024. For 2025/26, the new rates are fully integrated into HMRC's Self Assessment system — no manual adjustment is needed
Step 5: Check if Making Tax Digital affects your 2025/26 return
MTD for Income Tax became mandatory from 6 April 2026 for those with qualifying income above £50,000. Your 2025/26 return (covering 6 April 2025 to 5 April 2026) is the last return filed entirely under the traditional Self Assessment process for those moving to MTD.
Your 2025/26 return is still filed through HMRC's existing online service or commercial software, as normal, by 31 January 2027. From 2026/27 onwards, your return must be submitted through MTD-compatible software.
If your qualifying income is between £30,000 and £50,000, you will not be required to use MTD until April 2027.
Read our full guide: Making Tax Digital for Income Tax: What's Changing from April 2026
Step 6: File your return
You can file online from 6 April 2026. Filing early does not mean you pay early — the payment deadline is still 31 January 2027 regardless of when you submit.
Benefits of filing early:
- You know exactly what you owe, months in advance
- You have time to save or arrange a payment plan
- You can claim any refund sooner
- You avoid the January rush and potential system delays
- You can still go back and amend your return if needed
To file online, sign in to your HMRC Government Gateway account. You will need your UTR and National Insurance number. The online system guides you through each section and calculates your tax automatically.
If you use commercial software (such as FreeAgent, Xero, QuickBooks, or others), you can submit directly through the software to HMRC.
Step 7: Understand payments on account
If your Self Assessment bill for 2025/26 exceeds £1,000 and less than 80% was deducted at source through PAYE, HMRC will require payments on account towards the following year's bill. Each payment is 50% of the previous year's liability.
- First payment on account: due 31 January 2027 (alongside your 2025/26 balancing payment)
- Second payment on account: due 31 July 2027
If your income drops, you can apply to reduce payments on account using form SA303 on Gov.uk. Be cautious: if you reduce them too much, you may face interest charges on the shortfall.
Step 8: Pay your tax
The full amount of tax you owe for 2025/26 must be paid by 31 January 2027. HMRC accepts:
- Online banking (Faster Payments — usually same or next day)
- Direct Debit (set up through your HMRC account)
- Debit card online (personal credit card payments are no longer accepted, but corporate credit cards are still accepted — a non-refundable fee applies)
- At your bank or building society
- By cheque through the post (allow enough time for delivery)
- Through your PAYE tax code (if you submit by 30 December 2026 and owe less than £3,000)
- Budget Payment Plan (regular weekly or monthly payments, set up via your HMRC online account)
If you cannot pay in full, contact HMRC before the deadline to set up a Time to Pay arrangement. For debts up to £30,000, you can arrange this online without phoning. Instalments typically spread over up to 12 months.
What happens if you miss the deadlines
Late filing penalties
| How late | Penalty |
|---|
| 1 day | £100 (even if you owe no tax) |
| 3 months | £10 per day for up to 90 days (max £900) |
| 6 months | £300 or 5% of tax due, whichever is greater |
| 12 months | A further £300 or 5% of tax due, whichever is greater |
A return filed over 12 months late can incur penalties totalling £1,600 or more.
Late payment penalties
| How late | Penalty |
|---|
| 30 days | 5% of tax unpaid |
| 6 months | Additional 5% of tax still unpaid |
| 12 months | A further 5% of tax still unpaid |
HMRC also charges interest on unpaid tax from 1 February 2027. From 6 April 2025, the late payment interest rate is the Bank of England base rate plus 4% (increased from the previous base rate plus 2.5%).
You can appeal a penalty if you have a reasonable excuse — for example, serious illness, bereavement, or HMRC system failure. Appeals must be made within 30 days using form SA370 or through your HMRC online account.
The complete interactive checklist
Tick each item as you go. Your progress is saved in your browser — come back anytime.
Registration & access
Registered for Self Assessment (if first time: by 5 October 2026)
Have your Unique Taxpayer Reference (UTR)
Have your National Insurance number
Can sign in to HMRC Government Gateway
Employment income
P60 from each employer
P45 from any jobs left during the year
P11D — benefits in kind (company car, health insurance, etc.)
Self-employment records
Complete records of all business income received
All invoices issued during the year
Business bank statements
Allowable expense receipts and records
Mileage records (if claiming simplified expenses)
Working from home records — hours per month for the tiered flat rate
Property income
Rental income records or letting agent statements
Landlord expense records (repairs, insurance, agent fees)
Mortgage interest statements (for Section 24 tax credit)
Short-term holiday let income (now reported as standard property income)
Savings, investments & pensions
Bank and building society interest statements
Dividend statements from shareholdings
Capital gains records (shares, property, crypto sold)
Pension income statements (state and private)
Foreign income records
Deductions & reliefs
Pension contribution statements (and whether scheme uses relief at source or net pay)
Gift Aid donation records
Student loan type confirmed (Plan 1, 2, 4, or Postgraduate)
Marriage Allowance (if transferring to spouse)
Filing & payment
Return submitted online by 31 January 2027
Tax paid by 31 January 2027
Payments on account noted for 31 January and 31 July 2027 (if applicable)
Business records stored for at least five years (until 31 January 2032)
Non-business records stored for at least 22 months (until January 2028)
Track your 2025/26 income and expenses in Excel
Our Self Assessment 2025/26 Tracker has income logs, expense categories, quarterly summaries, and submission-ready figures — pre-set for the correct tax year.
View SA 2025/26 Tracker — £4.99
Sources
This article is for general information only and does not constitute tax advice. Tax rules can change — always verify key details against current Gov.uk guidance before acting. Article last reviewed against live Gov.uk sources on 13 April 2026.