If you are self-employed in the UK, you do not just pay income tax. There are three separate tax systems you need to understand - each with different thresholds, different payment mechanisms, and different deadlines. Most sole traders and small business owners have straightforward tax affairs once they know the rules. The problem is that nobody hands you a clear explanation when you start out.
This guide covers the current-year figures and the practical obligations - what you owe, when you pay it, and what you must do to stay on the right side of HMRC. All thresholds reflect the 2026/27 UK tax year (6 April 2026 to 5 April 2027) unless otherwise stated, and should be verified against HMRC published rates before you act on them.
Note on Making Tax Digital: From April 2026, self-employed people with combined gross income from self-employment and property above £50,000 must keep digital records and submit quarterly updates to HMRC using compatible software, in addition to the annual return. If your income is approaching or above this level, check the current MTD requirements at GOV.UK before your next filing period.
The Three Taxes Every Self-Employed Person in the UK Pays
Most people starting out assume self-employment means one tax bill. It does not. There are three distinct systems, and confusing them is how founders end up either underpaying or setting aside too much without understanding why.
Income Tax - paid on your profits above the Personal Allowance, collected through Self Assessment.
National Insurance (NI) - paid on your profits above separate NI thresholds, split across two classes (Class 2 and Class 4) for the self-employed.
VAT (Value Added Tax) - charged on your sales once your taxable turnover exceeds a registration threshold. It is not a tax on your profit - it is a tax on your revenue that you collect on HMRC's behalf.
Each of these operates independently. Your Income Tax is calculated on profit. Your NI is calculated on profit but at different rates. Your VAT obligation is triggered by turnover, not profit. They are billed and paid through different processes, and they kick in at different income levels.
Not the same system
Income Tax, National Insurance, and VAT are three separate tax systems. They each have different thresholds, different rates, and different payment timelines. Understanding them separately is the foundation of managing your tax position correctly.
Income Tax for the Self-Employed: Rates, Bands, and the Personal Allowance
Income Tax applies to your business profits - what is left after you have deducted your allowable business expenses from your income. You do not pay tax on the first chunk of your profits, because the Personal Allowance shields it. For 2026/27, the Personal Allowance is £12,570. This figure has been frozen since April 2022 and is due to remain at this level until at least April 2031. Profits below this threshold are tax-free.
Above the Personal Allowance, Income Tax is charged in bands. These rates apply in England, Wales, and Northern Ireland. Scottish taxpayers pay different rates set by the Scottish Government - if you are a Scottish taxpayer, check the Scottish income tax bands separately on the HMRC or Scottish Government website.
Basic rate: 20% on profits from £12,571 to £50,270
Higher rate: 40% on profits from £50,271 to £125,140
Additional rate: 45% on profits above £125,140
These bands apply for 2026/27 and are frozen until at least April 2031.
One point that trips up many new founders: your Personal Allowance tapers off once your income exceeds £100,000. You lose £1 of allowance for every £2 of income above that level. If your profits are approaching six figures, this is worth understanding before year-end.
Tax is on profit, not turnover
Income Tax is calculated on your net profit - your income minus allowable business expenses. If you invoice £40,000 but spend £10,000 on legitimate business costs, you are taxed on £30,000, not £40,000. Keeping accurate records of your expenses matters.
National Insurance for the Self-Employed: Class 2 and Class 4 Explained
National Insurance contributions (NICs) for the self-employed work differently from employee NI. As a self-employed person, you pay two types - and both are collected through your annual Self Assessment tax return.
Class 2 National Insurance
Class 2 NICs are a flat weekly rate relevant to your State Pension entitlement. The voluntary rate is £3.65 per week for 2026/27 (it was £3.50 for 2025/26 and £3.45 for 2024/25).
From April 2024, Class 2 NICs are no longer compulsory. If your profits are above the Small Profits Threshold (£7,105 for 2026/27), HMRC automatically treats Class 2 as paid - you receive a qualifying year for State Pension without making any payment.
If your profits are below the Small Profits Threshold, you can choose to pay them voluntarily to protect your entitlement.
Class 4 National Insurance
Class 4 NICs are a percentage of your profits above a lower threshold. For 2026/27:
6% on profits between £12,570 and £50,270
2% on profits above £50,270
Class 4 does not count towards your State Pension or benefits - it is simply a contribution to the national insurance system based on your earnings. Both Class 2 and Class 4 are calculated and paid as part of your Self Assessment return, so you do not need to make separate payments during the year.
Class 2 changes from April 2024
From the 2024/25 tax year, HMRC treats Class 2 NIC entitlement as paid for self-employed people with profits above the Small Profits Threshold (£7,105 in 2026/27) - no separate Class 2 charge applies.
Those with profits between the Small Profits Threshold and £12,570 receive a National Insurance credit. Those below the Small Profits Threshold may pay voluntarily to protect their State Pension record. Always verify the current position on the HMRC website or with a qualified accountant before filing.
When Do You Need to Register for VAT?
VAT is a different system entirely. It is not a tax on your profit - it is a consumption tax charged on your sales, collected by you on HMRC's behalf, and paid over to HMRC after deducting the VAT you have paid on your own business purchases.
You must register for VAT when your taxable turnover exceeds £90,000 in any rolling 12-month period. This threshold has been in place since April 2024 and remains unchanged for 2025/26 and 2026/27. The key word is turnover - not profit. If you are taking in £90,001 in revenue from VAT-liable sales, you must register, even if your profit on that turnover is modest.
You can also register voluntarily below the threshold - and there are sometimes good reasons to do so, particularly if your customers are VAT-registered businesses who can reclaim the VAT you charge them.
Mandatory registration: taxable turnover above £90,000 in any 12-month rolling period
Voluntary registration: available at any point below the threshold
Once registered, you must charge VAT on applicable sales, file VAT returns (usually quarterly), and pay HMRC the net amount owed
Not all goods and services are subject to the standard 20% rate - some are zero-rated or exempt, which changes the calculation
Missing the VAT threshold is a compliance risk
If your turnover crosses the £90,000 threshold and you do not register, HMRC can charge you the VAT you should have collected - even if you never actually charged it to your customers. Monitor your rolling 12-month turnover regularly, especially if your business is growing quickly.
Self Assessment: What It Is and What You Must Do Each Year
Self Assessment is HMRC's system for collecting tax from people whose income is not taxed at source. As a self-employed person, your business income is not automatically taxed when it arrives - so you are responsible for declaring it and paying what you owe.
You must register for Self Assessment if your gross self-employment income exceeds £1,000 in a tax year. The trading allowance exempts the first £1,000 of gross trading income from tax and reporting - once you exceed it, registration is required. Note: the trading allowance applies to gross income, not profits. Once registered, you file an annual tax return and pay the tax and NI owed.
The Annual Self Assessment Cycle
Register
Register for Self Assessment with HMRC. Do this by 5 October following the end of your first tax year of self-employment. The tax year runs from 6 April to 5 April.
File your return
Submit your Self Assessment tax return by 31 January following the end of the tax year. Online filing is standard. Paper returns must be submitted by 31 October. The return covers your income, expenses, and any other sources of income.
Pay your bill
Pay any tax and NI owed by 31 January. If you are also making Payments on Account (see below), a second payment is due by 31 July. Penalties and interest apply immediately if you miss these deadlines.
Keep records
Keep records of all income and expenses for at least five years after the 31 January deadline for that tax year. HMRC can open an enquiry into your return and you will need to produce your records.
Payments on Account: The HMRC System That Catches New Founders Off Guard
Payments on Account are advance payments towards your next year's tax bill. HMRC requires them when your Self Assessment bill exceeds a minimum threshold. For many new founders, the first time they encounter this, it comes as a significant surprise.
Here is how it works. When you file your first Self Assessment return and your tax bill is above £1,000, HMRC asks you to pay not just that year's bill on 31 January - but also 50% of that bill again as a payment on account towards the following year. A second payment of the remaining 50% is due by 31 July.
Illustrative example - based on a common UK founder scenario, not a specific documented case
A sole trader finishes their first full year in business with a tax and NI bill of £4,000. On 31 January, they expect to pay £4,000. Instead, HMRC bills them £4,000 plus £2,000 as the first payment on account for next year - a total of £6,000. A further £2,000 payment is then due by 31 July. This catches founders off guard, but it is predictable once you understand the system.
If your income is likely to be lower in the next tax year, you can apply to reduce your Payments on Account. But if you reduce them and your actual bill turns out to be higher, HMRC will charge interest on the shortfall. Build Payments on Account into your cash flow planning from year one.
How Much Should You Set Aside for Tax Each Month?
There is no universal figure that works for everyone, because it depends on your profit level, your expenses, and whether you have other sources of income. But a practical starting point exists.
For most sole traders earning modest profits in the basic rate band, setting aside around 25-30% of every payment you receive into a separate savings account will comfortably cover Income Tax, Class 2 and Class 4 NI, and give you a buffer for Payments on Account. If your profits are higher and you are approaching the higher rate band, increase this to 35-40%.
Keep your tax savings in a separate account - do not rely on your current account to have the money available when the bill arrives
Set aside a percentage of each invoice payment or income receipt, not a monthly flat amount - your income may vary
Factor in Payments on Account from your first year - your January bill will be larger than just the year's tax
Review your savings rate quarterly as your income changes - adjust up or down as needed
Use a simple rule, then refine it
Start with 25-30% as your default saving rate on gross income. Once you have filed your first Self Assessment return, you will have a real figure to work backwards from. Use that to calibrate your savings rate for year two.
The Allowable Expenses That Legally Reduce Your Tax Bill
The most direct way to reduce your tax bill is to claim every legitimate business expense you are entitled to. Allowable expenses reduce your taxable profit — which reduces both your Income Tax and your Class 4 NI liability at the same time.
HMRC's test is that the expense must be incurred wholly and exclusively for the purpose of the trade. Where an expense has a personal element, you can only claim the business proportion — for example, 60% of a phone bill if 60% of your usage is business-related. For a full breakdown of what qualifies and how to apportion mixed-use costs, see our guide to allowable expenses for sole traders. Office costs — stationery, software subscriptions, postage
Travel — business mileage at HMRC approved rates, train fares, parking for client visits
Equipment — laptops, tools, or machinery used in the business
Professional fees — accountant or solicitor fees for business matters
Marketing — website costs, ad spend, business cards
Use of home as office — a proportion of heating, electricity, and broadband
Training — courses directly relevant to your current trade
If you are using the cash basis method of accounting — the default for most sole traders — you claim expenses when they are paid, not when they are incurred. Keep receipts for everything. HMRC can ask you to substantiate any expense you claim.
Expenses reduce both Income Tax and NI
Every pound of legitimate expense you claim reduces your taxable profit — cutting both your Income Tax and Class 4 NI liability at the same time. Getting your expenses right is one of the highest-return tasks you do at year-end.
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