📋 Self Assessment · 2025/26

Self Assessment Summary

Complete UK Self Assessment calculator — income tax across all sources, Class 2/4 NIC for self-employed, student loan, pension relief, payments on account, penalty estimator, and key deadline tracker for 2025/26.

💼 Income Sources

Employment Income

Gross employment income (£)Total salary / wages before PAYE deductions

PAYE tax already paid (£)From P60 / payslips — offset against SA bill

Self-Employment / Trading

Self-employed profits (net, £)After allowable business expenses

Partnership profits allocated (£)

Property, Savings & Other

UK property income (profit, £)Rental income after allowable expenses

Savings interest (£)Bank/building society interest received

Dividend income (£)

Pension income (£)State pension + private pension payments

Capital gains (chargeable, £)After AEA and losses — from CGT calculator

Other taxable income (£)

🎯 Reliefs & Allowances

Personal pension contribs (net, £)Gross up ×100/80 for basic rate relief

Gift Aid payments (net, £)

Trading allowance used (£)Up to £1,000 for casual trading income

Property allowance used (£)Up to £1,000 for property income

Marriage allowance transfer (£)Up to £1,260 transferred from lower-earning spouse

Blind person's allowance?

⚙️ Settings

Tax year

Student loan repayment?

Previous year SA liability (£)Used to calculate payments on account

⚠️ Disclaimer Estimates only. Does not include Scottish income tax bands, all HMRC adjustments, or complex scenarios. Verify via GOV.UK Self Assessment →

📋 SA Bill Summary

2025/26 · all sources

📋

Enter your income details and click Calculate.

💳 Payments on Account

How Payments on Account WorkIf your SA bill is over £1,000 AND less than 80% was collected at source (PAYE), HMRC requires you to pay two advance payments ("payments on account") toward next year's tax. Each is 50% of the current year's SA liability. The balancing payment = final liability − two POAs already paid.

Your SA Liability

Current year SA liability (£)Income tax + NIC from SA — from Summary tab

Tax collected at source (PAYE, £)Must be <80% of total for POA to apply

Previous year SA POAs paid (£)1st + 2nd POA paid toward this year

Expect next year's tax to be lower?

💳 Payment Schedule

Payments on Account for 2025/26

💳

Enter your SA liability and click Calculate.

⚠️ Penalty & Interest Estimator

Late Filing

Filing deadline date

Date you filed (or plan to file)

Late Payment

Tax due (£)

Date tax was / will be paid

HMRC interest rate (% p.a.)

⚠️ Penalty Estimate

Filing + payment penalties & interest

⚠️

Enter dates and click Calculate.

📅 Self Assessment Key Deadlines — 2025/26 Tax Year

✅

6 April 2025 PASSED

Start of 2025/26 tax year. New rates and allowances apply: Class 4 NIC at 6%, employer NIC at 15%, Class 2 NIC voluntary at £3.50/week.

✅

31 January 2026 PASSED

2024/25 online return deadline — File SA return for 2024/25.
2024/25 balancing payment — Pay any remaining 2024/25 tax.
1st Payment on Account for 2025/26 — 50% of 2024/25 liability.

✅

5 April 2026 PASSED

End of 2025/26 tax year. Last day to use 2025/26 ISA allowance (£20,000), pension annual allowance, and capital losses.

📅

6 April 2026

Start of 2026/27 tax year. Dividend rate changes: basic 10.75%, higher 35.75%. BADR rate increases to 18%.

⏰

5 October 2026

Register for Self Assessment — Deadline to register with HMRC if this is your first SA return for 2025/26. Call HMRC or register online at gov.uk/register-for-self-assessment.

📄

31 October 2026

Paper SA return deadline — File paper 2025/26 return. Late paper: £100 immediate penalty then £10/day up to £900.

🔴

31 July 2026

2nd Payment on Account for 2025/26 — 50% of 2024/25 SA liability. Failure triggers 5% late payment penalty after 30 days.

🚨

31 January 2027

Online SA return for 2025/26 — File online or face £100 immediate penalty.
2025/26 balancing payment — Any remaining tax after POAs.
1st Payment on Account for 2026/27 — 50% of 2025/26 liability.

💡 Who Needs to File Self Assessment?

Must file if you:

✔Are self-employed with profits > £1,000

✔Have income over £100,000

✔Have untaxed income of any kind

✔Receive dividends > £10,000 or any dividends if higher rate taxpayer

✔Have rental income > £2,500 (below this, HMRC may adjust tax code)

✔Have CGT to pay

✔Claim Child Benefit and income > £60,000 (High Income Child Benefit Charge)

✔Are a company director (unless no pay from the company)

✔Have foreign income

Useful allowances to remember:

£1,000 — Trading allowance (casual income)

£1,000 — Property allowance

£500 — Dividend allowance (0% tax)

£1,000 — Personal Savings Allowance (basic rate)

£500 — PSA (higher rate)

£3,000 — Annual Exempt Amount (CGT)

£12,570 — Personal Allowance

£1,260 — Marriage allowance (transfer to spouse)

£20,000 — ISA annual allowance (gains/income exempt)

📚 SA Reference — 2025/26 Rates & Bands

Income Tax bands (England, Wales, N. 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%

Class 4 NIC (self-employed) 2025/26

Profits	Rate
Below £12,570	0%
£12,570 – £50,270	6%
Above £50,270	2%

Student Loan repayment thresholds 2025/26

Plan	Threshold	Rate
Plan 1	£24,990	9%
Plan 2	£27,295	9%
Plan 4 (Scotland)	£31,395	9%
Postgraduate	£21,000	6%

Late Filing Penalties

Lateness	Penalty
1 day late	£100 fixed penalty
3 months late	£10/day for up to 90 days (max £900)
6 months late	Greater of 5% of tax due or £300
12 months late	Greater of 5% of tax due or £300 (additional)

Late Payment Penalties

Lateness	Penalty
30 days late	5% of unpaid tax
6 months late	Further 5% of unpaid tax
12 months late	Further 5% of unpaid tax
Daily interest	7.75% p.a. (as of 2025/26) on unpaid amount

Reasonable Excuse — Avoiding Penalties HMRC may waive penalties if you have a "reasonable excuse" — e.g. serious illness, bereavement of a close relative, HMRC system failure, or unexpected hospital stay. It does not include forgetting, relying on an accountant who failed to file, or lack of funds. Always apply for appeal within 30 days of the penalty notice.

Class 2 NIC — Voluntary from April 2024 From 6 April 2024, Class 2 NIC is no longer compulsory for self-employed people with profits above the Small Profits Threshold (£6,725). However, paying voluntarily (£3.50/week in 2025/26) protects State Pension entitlement and access to contributory benefits. Check your National Insurance record at gov.uk/check-national-insurance-record.