UK Self Assessment Tax Calculator 2025/26

Estimate your income tax, personal allowance, and take-home pay for the 2025/26 tax year. Designed for sole traders, freelancers, and self-employed individuals in England, Wales, and Northern Ireland.

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£
Total revenue from your self-employment or freelance work before any deductions
£
Costs incurred wholly and exclusively for your business (office, travel, equipment, etc.)
£
Any dividend income you expect to receive (taxed at 8.75%/33.75%/39.35% above the £500 allowance)
📈 Your UK Self Assessment Summary
Taxable Income £0
Personal Allowance £0
Income Tax Due £0
Take-Home Pay £0
ItemAmount
Gross Self-Employment Income£0
Allowable Business Expenses£0
Net Profit (after expenses)£0
Personal Allowance£0
Taxable Income (after Personal Allowance)£0
Dividend Income£0
Income Tax Due£0
Effective Tax Rate0%

💸 Understanding Your Self Assessment

This calculator estimates your income tax only for the 2025/26 tax year. Your actual Self Assessment bill may also include Class 2 and Class 4 National Insurance contributions, which are not included in this estimate.

The Personal Allowance of £12,570 is gradually reduced by £1 for every £2 of income above £100,000, creating an effective 60% marginal rate in the £100,000–£125,140 band.

File by 31 January — Missing the deadline incurs an automatic £100 penalty
Claim all allowable expenses — Reduce your tax bill by deducting genuine business costs
Payments on account — If your bill exceeds £1,000, HMRC expects two advance payments each year
Use the £500 dividend allowance — Dividend income below £500 is tax-free
Tax Disclaimer: This calculator provides estimates for informational purposes only. It does not include National Insurance contributions, student loan repayments, or the High Income Child Benefit Charge. Actual tax liabilities depend on your individual circumstances. Consult a qualified accountant or tax adviser for advice specific to your situation.

Frequently Asked Questions

Answers to common questions about UK Self Assessment and income tax

You must register for Self Assessment if you are self-employed as a sole trader with gross income over £1,000, a partner in a business partnership, or if you have untaxed income over £2,500 from investments, rental properties, or tips. You also need to register if your income from savings or investments exceeds £10,000, or if you need to pay the High Income Child Benefit Charge. Registration is done via the HMRC website and you must do so by 5 October following the end of the tax year.
For 2025/26, the UK income tax bands (England, Wales, and NI) are: Personal Allowance (0%) on taxable income up to £12,570; Basic Rate (20%) on income from £12,571 to £50,270; Higher Rate (40%) on income from £50,271 to £125,140; and Additional Rate (45%) on income over £125,140. Scotland has its own bands set by the Scottish Parliament, which differ from the rest of the UK.
Your Personal Allowance (normally £12,570) is reduced by £1 for every £2 your adjusted net income exceeds £100,000. This means your allowance is completely gone once your income reaches £125,140. This creates an effective marginal tax rate of 60% on income between £100,000 and £125,140, making this a crucial bracket for tax planning. Pension contributions and charitable donations can help reduce your adjusted net income and restore some of your allowance.
For the 2025/26 tax year, the key deadlines are: register for Self Assessment by 5 October 2026, file your online tax return by 31 January 2027, and pay any tax due by 31 January 2027. Payments on account may also be required if your tax bill exceeds £1,000. Missing the filing deadline incurs an automatic £100 penalty, with further daily penalties if you are more than 3 months late. Interest is charged on late payments.
As a sole trader, you can claim allowable expenses that are incurred wholly and exclusively for your business. Common expenses include: office costs (rent, rates, insurance, utilities), travel expenses (fuel, parking, train fares, accommodation), staff costs (salaries, pensions, NI), stock and raw materials, professional fees (accountants, solicitors, bookkeepers), marketing and advertising, and the cost of using your home for business (simplified flat rate of £6–£26 per month depending on hours worked). Personal expenses and client entertainment are strictly not deductible.
Dividends are taxed at different rates than earned income and benefit from a £500 dividend allowance for 2025/26. Above this allowance, dividends are taxed at: 8.75% (basic rate), 33.75% (higher rate), and 39.35% (additional rate). Dividends are treated as the top slice of your income and use up your basic and higher rate bands. This makes dividends significantly more tax-efficient than salary for company directors extracting profits from their own limited company.
Yes, self-employed sole traders pay National Insurance contributions (NICs). For 2025/26, you pay Class 2 NICs at £3.45 per week on profits over £12,570 (with the option to pay voluntarily below this threshold to protect your State Pension). You also pay Class 4 NICs at 6% on profits between £12,570 and £50,270 and 2% on profits above £50,270. National Insurance counts toward your State Pension entitlement and certain benefits. Limited company directors pay NI differently via their payroll salary.
You must register for Self Assessment with HMRC by 5 October following the end of the tax year in which you started self-employment. For example, if you started trading in the 2025/26 tax year (ending 5 April 2026), you must register by 5 October 2026. Registration is done online via the HMRC website. You will receive a Unique Taxpayer Reference (UTR) and need to file your first return by 31 January 2027. Late registration can result in penalties, so it is important to register as soon as you start trading.

What Is UK Self Assessment Tax?

Self Assessment is the system HMRC uses to collect income tax from individuals who do not have enough tax automatically deducted from their income. Unlike employees who pay tax through PAYE (Pay As You Earn), sole traders, freelancers, and company directors are responsible for reporting their own income and calculating their own tax each year. You must file a Self Assessment tax return if you earned more than £1,000 from self-employment in a tax year, or if you have other untaxed income such as rental income, investment returns, or tips. The tax year runs from 6 April to 5 April, and your return is due by the following 31 January.

UK Income Tax Rates for 2025/26

The 2025/26 tax year maintains the same income tax bands as the previous year for England, Wales, and Northern Ireland. The personal allowance remains frozen at £12,570, meaning the first £12,570 of your taxable income is tax-free. The basic rate of 20% applies to the next £37,700 of taxable income (up to £50,270 total). The higher rate of 40% applies to taxable income between £50,271 and £125,140, and the additional rate of 45% applies to income over £125,140. The personal allowance taper for those earning over £100,000 remains in place, effectively creating a 60% marginal rate in the £100,000 to £125,140 band.

How the Personal Allowance Works

The Personal Allowance is the amount of income you can earn each year without paying tax. For 2025/26, the standard Personal Allowance is £12,570. If your income is above £100,000, your Personal Allowance is reduced by £1 for every £2 of income above the threshold. This means that once your income reaches £125,140, your Personal Allowance is completely eliminated. You can reduce your adjusted net income (and potentially restore some or all of your Personal Allowance) by making pension contributions or charitable donations through Gift Aid. This makes pension contributions particularly valuable for those earning between £100,000 and £125,140.

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