Going Self-Employed: Your First 90 Days Tax Checklist (2026/27)
Just gone self-employed in the UK? The first 90 days set up everything that follows: registering with HMRC, getting a UTR, opening the right bank account, tracking expenses and understanding Class 4 NI at 6%. Here is the practical checklist for 2026/27.
Going self-employed is exciting, but the admin you set up in the first three months shapes how stressful your first tax return will be. Get the foundations right now and Self Assessment becomes a 30-minute job rather than a January nightmare. Here is the practical checklist for anyone starting out in the 2026/27 tax year.
Days 1 to 14: Tell HMRC and get your UTR
The first job is registering as self-employed. You can do this online through your HMRC account. The legal deadline is 5 October following the end of the tax year you started in, so if you began trading in 2026/27 you have until 5 October 2027. There is no benefit to leaving it, though, and a late registration can trigger a penalty if it means you miss the tax owed.
When you register, HMRC issues a Unique Taxpayer Reference (UTR). This 10-digit number identifies you on every return you file. It usually arrives by post within 10 working days, so do not leave registration until the last minute.
If your gross self-employed income for the year will be under 1,000 pounds, the trading allowance covers you and you do not need to register at all. The moment you expect to exceed 1,000 pounds gross, register.
Days 1 to 30: Separate your money
Open a dedicated bank account for your business income and expenses. As a sole trader this is not a legal requirement, but it is the single best decision you can make. One account in, one account out, and your bookkeeping practically writes itself.
This matters more than ever because of Making Tax Digital for Income Tax (MTD ITSA). From April 2026 anyone with qualifying income over 50,000 pounds must keep digital records and send quarterly updates to HMRC. From April 2027 the threshold drops to 30,000 pounds. A clean bank account feeds straight into compatible software.
While you are at it, set up a separate savings pot for tax. A good rule of thumb for a basic-rate sole trader is to move 25 to 30% of every payment received into that pot. It covers income tax plus Class 4 NI and stops the bill being a shock.
Days 1 to 30: Start tracking expenses from day one
Every allowable business expense you record reduces your taxable profit. If you spend 5,000 pounds on genuine business costs, a basic-rate taxpayer saves 20% income tax plus 6% Class 4 NI on that amount, which is 1,300 pounds. Expenses you forget to record are money left with HMRC.
Common allowable expenses for a new sole trader include:
| Category | Examples |
|---|---|
| Office costs | Stationery, phone, business software, postage |
| Travel | Mileage at 45p per mile (first 10,000), train fares, parking |
| Premises | Rent, business rates, a share of home costs if you work from home |
| Stock and materials | Goods for resale, raw materials, direct costs |
| Professional fees | Accountant, insurance, bank charges, subscriptions |
| Marketing | Website, advertising, business cards |
Keep a digital copy of every receipt. A photo in a dedicated app or folder is fine. The key is to capture it at the time, not to reconstruct it in January.
Days 30 to 60: Understand what you will actually owe
Self-employment tax is not one charge but two stacked together: income tax and Class 4 National Insurance.
For 2026/27 the figures are:
- Personal allowance: 12,570 pounds tax-free
- Basic rate: 20% on profits from 12,571 to 50,270 pounds
- Higher rate: 40% on profits above 50,270 pounds
- Class 4 NI: 6% on profits from 12,570 to 50,270 pounds, then 2% above
So a sole trader making 30,000 pounds of profit pays roughly 3,486 pounds income tax plus 1,045 pounds Class 4 NI, a combined bill of about 4,531 pounds. That is why the 25 to 30% savings habit matters.
Class 2 NI is no longer a mandatory weekly charge. If your profits fall below the 7,105 pound small profits threshold, you can choose to pay voluntary Class 2 at 3.65 pounds a week to keep building qualifying years toward your State Pension. For many low-profit first years, this small voluntary payment is excellent value.
Days 30 to 60: Decide if you need to register for VAT
You must register for VAT once your rolling 12-month taxable turnover exceeds 90,000 pounds, or if you expect to cross it in the next 30 days. The deregistration threshold is 88,000 pounds.
In your first 90 days you are unlikely to be near this, but it is worth knowing the number so you can watch for it. Some new businesses choose to register voluntarily before they hit the threshold, usually to reclaim VAT on start-up costs or to look more established to business customers. Most sole traders selling to the public are better off staying unregistered until they have to.
Days 60 to 90: Choose your record-keeping system
You do not need expensive software on day one, but you do need a system you will actually use. Options range from a simple spreadsheet to full bookkeeping apps.
If your income is heading toward the 50,000 pound MTD ITSA threshold for April 2026, or the 30,000 pound threshold for April 2027, choose MTD-compatible software now rather than switching later. Getting into the habit of recording transactions weekly is far easier than a quarterly catch-up.
A weekly 15-minute routine of categorising transactions and photographing receipts keeps everything current. It is the difference between a calm return and a frantic one.
Days 60 to 90: Diarise the deadlines
Put these dates in your calendar with reminders:
| Date | What is due |
|---|---|
| 5 October 2027 | Deadline to register for 2026/27 if not already done |
| 31 January 2028 | Online Self Assessment filing and tax payment for 2026/27 |
| 31 January 2028 | First payment on account (if your bill exceeds 1,000 pounds) |
| 31 July 2028 | Second payment on account |
Payments on account catch out almost every first-time sole trader. If your tax bill is over 1,000 pounds, HMRC asks you to pay half of next year's estimated bill in advance, in two instalments. In your first year that can mean paying 150% of your bill in one January. Knowing it is coming lets you save for it.
The 90-day mindset
The work you do in these three months is mostly invisible. Nobody pays you to register a UTR or categorise a receipt. But it is the scaffolding that makes self-employment sustainable. A clean bank account, a tax savings pot, a weekly bookkeeping habit and a diary full of deadlines will save you hundreds of pounds and hours of stress every single year.
Start the habits small and keep them consistent. By the time your first return is due, everything will already be in place.
Frequently asked questions
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