Self-Employed Tax Calculator UK 2026/27 — Income Tax & Class 4 NI

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How Self-Employed Tax Works

Unlike employees, self-employed people pay Income Tax and National Insurance once a year via Self Assessment, not deducted automatically from pay. You're taxed on profit (income minus allowable expenses), not turnover.

Contribution	Rate 2026/27
Income Tax	Same bands as employees: 0% / 20% / 40% / 45%
Class 4 NI	6% on profit £12,570–£50,270, 2% above
Class 2 NI	Not payable if profits exceed the Small Profits Threshold — NI credits applied automatically since the 2024 reform

Payments on account may also apply — HMRC can require you to pay 50% of next year's estimated bill in advance, twice a year.

Get Your Books & Tax Handled Properly

This calculator gives an estimate — but self-employed and dividend income both come with Self Assessment obligations, allowable expenses, and filing deadlines that are easy to get wrong without support.

New to self-employment or a limited company: get set up correctly from day one — VAT registration, expense tracking, Self Assessment.
Mixed salary + dividend income: an accountant can model the most tax-efficient salary/dividend split for a director-shareholder.
Approaching a filing deadline: avoid late-filing penalties with a fixed-fee online accountant.
Growing side income: know exactly when you cross into needing to register for Self Assessment.

Online accountants like Crunch, Osome and Tide Accounting handle Self Assessment and limited company filings at a fixed monthly fee, built for freelancers and small companies.

Compare Online Accountants →

Transparency & Methodology

Self-Employed Tax Calculator

Independent, Open-Source Estimator

An independent calculator applying published HMRC/gov.scot/DWP rates deterministically — no AI estimate, no official affiliation.

Methodology & Sources

Figures are public HMRC/gov.scot/DWP rates. For your exact position, use gov.uk/estimate-income-tax.

Not Tax or Legal Advice

Information only. Consult the Chartered Institute of Taxation or an adviser via the FCA Register.

Open Source

Formulas are public. Inspect on GitHub.

Frequently Asked Questions

How is self-employed tax different from PAYE?

Self-employed people pay Income Tax and Class 4 NI annually via Self Assessment based on profit, rather than having it deducted automatically each payday like PAYE employees.

What is Class 4 National Insurance?

Class 4 NI is paid by self-employed people on profits above £12,570 — 6% between £12,570 and £50,270, then 2% above, calculated alongside Income Tax via Self Assessment.

Do I still need to pay Class 2 NI?

Since the April 2024 reform, most self-employed people with profits above the Small Profits Threshold get NI credits automatically without paying Class 2 — though voluntary Class 2 payments remain available for those below the threshold who want to protect their State Pension record.

What are payments on account?

If your Self Assessment tax bill exceeds £1,000, HMRC typically requires two advance "payments on account" (each 50% of your prior year's bill) toward the following year's tax, due 31 January and 31 July.