Your first year self-employed — the complete checklist

Updated: 14/07/2026 · 8 min read

Going self-employed in the UK is simpler than the horror stories — provided a handful of things are done at the start rather than “before the tax return”. This checklist walks through all of it: registration, the first receipt, and the money set aside for the January bill.

Week one — the paperwork

Register for Self Assessment on gov.uk (your UTR arrives by post)
Construction? Register for CIS as soon as the UTR lands (20% deductions instead of 30%)
Open a SEPARATE account for business money (need not be a “business account” — just separate)
Sort insurance appropriate to the trade (public liability is near-essential on sites and in clients’ homes)

From day one — the records habit

The most expensive first-year mistake is “I will sort receipts later”. Later means faded, lost and forgotten — and every one of them is real money at filing time.

Every business purchase: photograph the receipt IMMEDIATELY (10 seconds)
Email invoices: forward to your private intake address
Let categories be assigned automatically
CIS: file every monthly deduction statement the day it arrives

Money — the 25–30% rule

Move 25–30% of every paid invoice into a separate tax pot. Your first January can bring a bill for the whole year PLUS a 50% advance for the next (payments on account) — painless with a pot, brutal without one.

Sales invoices

Number sequentially with no gaps (INV-001, INV-002…)
Complete details: yours, the client’s, description, amount, payment terms, bank details
Keep digital copies — they are your income records
Chase late payers — an unpaid invoice pays no bills

Year-one calendar

5 October (after your first tax year ends) — registration deadline
31 January — online return + payment
31 July — second payment on account (if due)
Monthly: 30 minutes of document tidying (zero, if capture is digital and immediate)

What NOT to do

Do not mix private and business spending in one account
Do not delay registering “until it takes off” — penalties are real
Do not bin receipts after typing them into a spreadsheet — the image is the evidence
Do not ignore brown envelopes from HMRC — they do not expire quietly

Every receipt captured, categorised and audit-ready.

Snap a photo or forward the email — Reclaim Day reads the vendor, amounts, VAT and date for you.

Start free

Frequently asked questions

When must I register as self-employed?+

By 5 October after the end of the tax year you started in. Practically: do it immediately — you will need the UTR sooner than you think.

Do I need a business bank account?+

As a sole trader, not legally — but a separate account is the foundation of clean records. Some banks’ terms require a business account for business use.

How much should I save for tax?+

A working rule: 25–30% of profit. Less under CIS (20% is already deducted), more at higher incomes. Calibrate after your first return.

Can I do the first return myself?+

Simple cases, yes — through your HMRC account. With CIS, a parallel job, or larger expenses an accountant usually recovers more than they cost.

This guide is general information, not tax advice. Rules and figures change — check gov.uk (HMRC) for current rates, and speak to an accountant about your situation.