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Tax for sole trader — start here

Sole-trader tax is mechanically simple but cash-flow brutal in the first profitable January because of payments on account.

If you're a UK sole trader, you pay Income Tax + Class 4 NI on your trading profit through Self Assessment, with Class 2 NI handled inside the same SA return. The first £1,000 of trading income is covered by the trading allowance; above that you must register, file, and pay by 31 January after the tax year ends. From April 2026 most sole traders with turnover above £50k fall into MTD ITSA (above £30k from April 2027).

Key facts

Trading allowance: first £1,000 of gross self-employed income tax-free, no reporting needed. (as of 2025-04-06)
Class 2 NI is collected via SA at £3.45/week voluntary rate for 2024/25; Class 4 NI is 6% between £12,570 and £50,270 then 2% above. (as of 2025-04-06)
Self Assessment filing deadline is 31 January following the tax year (so 2025/26 return due 31 Jan 2027). (as of 2025-04-06)
MTD ITSA mandation: turnover >£50k from 6 April 2026, >£30k from 6 April 2027, >£20k from 6 April 2028. (as of 2025-04-06)
Cash basis is now the default for unincorporated businesses from 2024/25 onwards (Finance (No.2) Act 2023). (as of 2024-04-06)

Deadlines that matter for you

5 October 2026
Register for Self Assessment if you started trading in 2025/26 and haven't filed before.
If missed: Failure-to-notify penalty — up to 100% of tax due where deliberate, typically 30% for careless.
31 January 2027
Online Self Assessment filing deadline for 2025/26 + balancing payment + first payment on account for 2026/27.
If missed: £100 immediate fixed penalty + daily £10 penalties after 3 months + 5% surcharges + interest at HMRC rate.
31 July 2027
Second payment on account for 2026/27 due.
If missed: Late-payment interest at HMRC rate (Bank of England base + 4%) + 5% surcharge after 30 days.
6 April 2026
MTD ITSA mandation begins for sole traders + landlords with combined gross income above £50,000.
If missed: Quarterly-update failure points; £200 fixed penalty once 4 points accrued; further points for missed final declaration.

What most people in your position get wrong

Treating the £1,000 trading allowance as a tax-free band on top of normal expenses.
It's an either/or: either deduct actual expenses, or use the allowance — never both. For high-cost trades the actual-expense route wins.
Typical cost: Typical over-payment: £100–£400 per year depending on margin.
Forgetting Class 2 NI when profit is low — losing State Pension qualifying years.
Class 2 became voluntary below the Small Profits Threshold from 6 April 2024, but voluntary payment (£3.45/week 2024/25) protects State Pension entitlement. Decide explicitly; do not default to skipping.
Typical cost: Lost State Pension years: ~£328/year of pension per missing year at full new State Pension rate.
Missing payments on account — being shocked by a doubled January bill.
Each January you pay last year's balance + 50% of next year's estimate; another 50% in July. Budget for ~150% of the tax bill the first January after a profit jump.
Typical cost: Late-payment surcharge: 5% at 30 days + 5% at 6 months + 5% at 12 months + daily interest.
Assuming MTD ITSA doesn't apply because turnover is 'only' £55k.
Mandation is based on combined gross self-employment + property income above £50k from April 2026 — turnover (not profit), and combined across all sole-trade + landlord sources.
Typical cost: MTD points system: £200 fixed penalty once 4 points accrued in a 12-month period.

Who this is for

You trade in your own name (not through a limited company) and report your business profit through Self Assessment. Includes freelancers, single-handed tradespeople, online sellers crossing the £1,000 trading allowance, and partners in unincorporated partnerships.

Who this is NOT for

If you operate through a limited company, see /start-here/ltd-director. If your income is purely employment with a side hustle below £1,000 gross, you may not need to register — see /start-here/side-hustle. Landlords with property income only should see /start-here/landlord.

Start with these guides

Self Assessment — full guide →

Registering, filing, payments on account, payments dates, penalties.

Trading allowance £1,000 →

How the partial-relief option works and when to choose expenses instead.

Cash basis (now default) →

Cash-in / cash-out accounting from 2024/25 onwards.

Simplified expenses →

Flat-rate mileage, home-as-office, live-in business use.

Class 2 NI — voluntary mechanics →

How voluntary Class 2 protects State Pension entitlement after April 2024.

Pre-trading expenditure →

Claiming costs incurred before the trade started.

MTD ITSA timeline + thresholds →

Phase-in by income level from April 2026 onwards.

Useful calculators

Income Tax calculator →

Profit-after-tax across bands and Personal Allowance taper.

Self-Employment Self Assessment overview →

Walk-through of the SA mechanics for sole traders.

Go deeper

In plain English

You are the business. There is no separate company. HMRC taxes your profit (income minus allowable expenses) at the same rates as employment income, with NI on top. The big difference vs PAYE is timing — you pay tax retrospectively each January, often with a payment on account towards the following year. Get into the habit of moving ~30% of every receipt into a tax-saver pot and you'll never get caught short.

Statute reference

Income Tax (Trading and Other Income) Act 2005 (ITTOIA 2005); Income Tax Act 2007 Part 4 (loss relief); Social Security Contributions and Benefits Act 1992 ss.11–18 (Class 2 + 4 NI); Taxes Management Act 1970 s.7 (notification) + s.8 (returns); Finance (No.2) Act 2023 Sch.10 (cash basis default).

Worked example

Self-employed graphic designer, second year of trading, 2025/26 profit £42,000, no other income.

Trading profit (after expenses): £42,000
Personal Allowance (2025/26): £12,570
Taxable profit: £29,430

Calculation: Income Tax: £29,430 × 20% = £5,886. Class 4 NI: (£42,000 − £12,570) × 6% = £1,765.80. Class 2: voluntary, £179.40/year if paid. Total Self Assessment liability: ~£7,652 + first payment on account for 2026/27 of ~£3,826 = ~£11,478 due 31 Jan 2027.

Outcome: Effective tax + NI rate on profit: ~18.2%. Cash impact January 2027 is roughly 150% of the full-year tax bill because of the payment-on-account mechanism — easy to under-budget for in the first profitable January.

Last reviewed: 2026-05-24. Statute references are for orientation, not advice. Always confirm specifics for your situation against current HMRC guidance or a regulated professional.