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Self Employed Tax Calculator
Sole trader income tax & National Insurance — 2025/26
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Self Employed Tax Breakdown — 2025/26
Income Tax—
Class 2 NI (flat rate)—
Class 4 NI—
Total tax & NI—
Net profit after tax—
⚠️ Self Assessment tax is paid in two payments on account (31 Jan and 31 Jul) plus a balancing payment. Keep money aside throughout the year — typically 25–30% of profit for basic rate taxpayers.

How Are Sole Traders Taxed?

As a self-employed sole trader you pay income tax on your profits (income minus allowable expenses) plus Class 2 and Class 4 National Insurance. You report this through a Self Assessment tax return each year, with payment due by 31 January.

Allowable Business Expenses

You can deduct allowable expenses from your income to reduce your taxable profit. Common allowable expenses include: office costs, travel (business only), stock and materials, staff costs, financial and legal costs, marketing, and a portion of home office costs.

Self Assessment Deadlines 2025/26

DeadlineWhat's Due
5 October 2025Register for Self Assessment (if new)
31 October 2025Paper tax return deadline
31 January 2026Online return & tax payment deadline
31 July 2026Second payment on account

Should I Go Limited?

When profits exceed approximately £30,000–£35,000, incorporating as a limited company can save tax. Directors can take a low salary (avoiding higher NI) and dividends (taxed at lower rates). However, there are additional admin costs and responsibilities involved.