Small businesses are the backbone of the UK economy. They are defined by their size, flexibility, and ambition. A small business can be anything from a local cafe to a growing tech startup, and they typically employ fewer than 50 people and turnover less than £10 million a year.  

HMRC classifies businesses in the UK in two separate ways. By legal structure (how it’s owned and legally protected) and by size category (which determines your tax and filing obligations). It is important to understand both, as they shape everything from how much admin you do to how much tax you pay. 

How your business is legally structured affects your liability, your tax treatment, and your reporting obligations. Getting your structure and size category right isn’t just a technicality; it determines your tax rates, your filing deadlines, and how much financial detail you’re legally required to disclose. Getting it wrong means you’re at risk of paying more tax than necessary. That’s where Fynax comes in — our expert accountants figure out the right structure and classification for you, so you don’t have to worry about any of it

The three most common structures are:

Alongside legal structure, size category also determines your obligations.

Companies House and HMRC classify businesses into three main brackets if they meet at least two of the specified criteria: 

Running a small business means wearing every hat, and financial admin is often the one that gets pushed to the bottom of the pile. Between staying compliant with HMRC and keeping on top of Companies House filings, it can be easy to feel like you’re managing paperwork instead of growing your business. 

That’s where we come in. We take the financial administration off your plate. This includes bookkeeping, tax, payroll, filings, and the deadlines that come with all of it, so you can focus on putting your time and energy into actually running your business, not chasing compliance.