When do I have to register with HMRC?

Sole traders: by 5 October after the end of the tax year in which you started trading. Limited companies: for Corporation Tax within 3 months of starting to do business. Don't leave either to the deadline.

Do I need an accountant from day one?

Sole traders with simple affairs often self-prepare for year one. Most limited companies benefit from an accountant from incorporation onwards — the cost is usually outweighed by tax savings and avoided penalties.

What if I miss a deadline?

HMRC and Companies House both charge automatic penalties that grow over time. File anything outstanding immediately and pay what you can — penalties are easier to negotiate when you're in active compliance.

New Business Finance Checklist (UK)

A no-fluff checklist for the first year of a new UK business — what to set up, when to set it up, and what tends to go wrong if you don't.

Written and reviewed by the Editorial team

Business Finance Toolkit · Independent guidance for UK small businesses

Last updated: 21 May 2026

Short answer

The order that works: pick a structure, register with HMRC (and Companies House if it's a limited company), open a dedicated business account, set up basic bookkeeping with a tax pot, send compliant invoices, and put a single recurring date in the diary for monthly finance review. Everything else slots in around those six anchors.

Before you start trading

Most of the financial mistakes new businesses make are made before they ship anything. A handful of decisions taken in the first fortnight quietly compound for years — the legal structure you choose, the bank account you open, the way you separate personal and business money, and whether you put a date in the diary to review the numbers.

Pre-launch

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Week one of trading

Week one

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First month

By the end of month one, the muscle memory of running money through the business should be in place: invoices go out promptly, receipts get captured, the bank account is reconciled, and a percentage of every payment received is moved straight to the tax pot.

First month

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First quarter

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First year

The deadlines that matter

Sole traders: Self Assessment is due 31 January after the tax year ends. Limited companies: Confirmation Statement annually, accounts to Companies House within 9 months of year end, and Corporation Tax payable 9 months and 1 day after year end. Diary these the day you register.

First year

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Download the checklist

A spreadsheet version of every item above, with columns for date completed, owner and notes.

New Business Finance Checklist (CSV)Checklist

Frequently asked questions

Related guides

Sole trader vs limited company

How to register as a sole trader

How to set up a limited company

Monthly finance review checklist

Affiliate disclosure

Some links on this page are affiliate or referral links. If you apply through them we may receive a commission, at no extra cost to you. This does not influence our editorial recommendations — see our editorial policy and affiliate disclosure.

Not financial advice

Information on this page is general guidance for UK small businesses and is not financial, tax or legal advice. Tax rules, allowances and product terms change. Always check current information with HMRC, Companies House or a qualified professional before making decisions.