SimpleReturns

Filing your company tax return yourself vs using an accountant

Reviewed by Lee Jones, Founder · Updated 17 July 2026
The short answer

It depends on how complicated your company is. When HMRC sends a notice you must file a Company Tax Return, even in a loss year, and HMRC itself says you can use an accountant or do it yourself. For a straightforward small company, self-filing is usually fine. For anything tangled, an accountant earns their fee.

Official source. This guide is a plain-English summary of official GOV.UK guidance, not advice. The authoritative source is Company Tax Returns on gov.uk. Always rely on that over our summary.

What do you actually get from an accountant?

A good accountant is not just a form-filler. You are paying for judgement. When a cost sits in a grey area and you genuinely do not know if it counts, they make the call and stand behind it. When your company is part of a group, owns other companies, or has other companies connected to it, the tax gets more involved and the sums change, and that is exactly where experience pays off.

Some situations almost always want a professional. If your company works in construction and deals with the Construction Industry Scheme, or if your contracts fall under the off-payroll (IR35) rules, those are real areas of complexity where an accountant is the right call. We will not pretend otherwise.

And there is peace of mind. Even when you hire an accountant, the law still treats you, the director, as responsible for your company's records and accounts. A trusted accountant does not remove that responsibility, but it does mean someone experienced has looked at your numbers before they go to HMRC, which many directors sleep better for.

What does filing it yourself give you?

Control, cost, and speed. You are not waiting on anyone else's diary, and you are not paying a recurring fee for a return that, for a simple company, is fairly mechanical.

For a lot of small companies the picture really is simple. One or two people, money in from a handful of customers, ordinary running costs out, no group, no property empire, nothing exotic. If that sounds like your company, the return is mostly a matter of getting the figures in the right boxes rather than making difficult judgement calls.

Doing it yourself also means you understand your own numbers, which is no small thing. You see where the money went, you learn what counts and what does not, and next year is easier because of it.

So which one is right for you?

Be honest about your company. An accountant is the right choice if any of these ring true:

  • You are part of a group, own other companies, or have other companies connected to yours.
  • You work through the Construction Industry Scheme, or your contracts fall under the IR35 off-payroll rules.
  • You have costs you genuinely cannot classify, or the year was unusual (a big one-off, a loss you want to carry, assets bought and sold).
  • The idea of getting it wrong keeps you up at night, and paying to hand that worry to someone is worth it to you.

Filing yourself is the right choice if your company is straightforward:

  • One or a few people, ordinary trade, income from customers and ordinary running costs.
  • No group, no connected companies, nothing on the list above.
  • You are willing to spend an hour understanding your own figures.

There is no medal for doing it the hard way, and no shame in paying an expert. The goal is a correct return filed on time. Whichever route gets you there for your company is the right one.

Whatever you choose, do not miss the deadline. File one day late and HMRC charges £200, with another £200 at three months, and after that it starts adding 10% of any unpaid tax. The flat £200 charges land even in a loss-making or nil year, so the cheapest return is always the one filed on time.

What filing looks like with us

We built SimpleReturns for the self-file lane, for the straightforward small company that does not need a full accountant but does not want to wrestle HMRC software alone. This matters more now that HMRC's old free filing service has closed, which means self-filers need commercial software to file at all.

The formula is deliberately plain. You upload a bank statement, answer a few questions in everyday English, and we turn that into the two documents your company owes: the CT600 tax return for HMRC and the micro-entity accounts for Companies House. You see and check every figure before anything is sent. Nothing is filed behind your back. It is £99, and that covers both filings, with nothing to pay to start and see how it looks.

If you would rather understand the full step-by-step first, our guide on filing your own corporation tax walks the whole journey through.

And if, reading the list above, your company is complex, grouped, or you are simply not sure, an accountant is the right call, and we would tell you the same in person. We are here for the straightforward ones.

Common questions

Do I have to use an accountant to file my Company Tax Return?

No. HMRC itself says you can get an accountant to prepare and file your tax return, or do it yourself. For a straightforward one-person or small company, doing it yourself is usually fine. For anything tangled, an accountant earns their fee.

Am I still responsible if my accountant files for me?

Yes. Even when you hire an accountant, the law still treats you, the director, as responsible for your company's records and accounts. A trusted accountant does not remove that responsibility, but it does mean someone experienced has looked at your numbers before they go to HMRC.

When is an accountant clearly the right choice?

When your company is part of a group or has connected companies, when you work through the Construction Industry Scheme or fall under the IR35 off-payroll rules, when you have costs you genuinely cannot classify, or when the year was unusual. Those are real areas of complexity where an accountant is the right call.

What happens if I miss the filing deadline?

File one day late and HMRC charges £200, with another £200 at three months, and after that it starts adding 10% of any unpaid tax. The flat £200 charges land even in a loss-making or nil year, so the cheapest return is always the one filed on time.

Decided the self-file lane is you?

You upload a bank statement, answer a few questions in everyday English, and we turn that into the two documents your company owes: the CT600 tax return for HMRC and the micro-entity accounts for Companies House. You see and check every figure before anything is sent. It is £99, and that covers both filings, with nothing to pay to start.

Start your return

And if your company is complex, grouped, or you are simply not sure, an accountant is the right call, and we would tell you the same in person.

General guidance, not advice. This guide explains how the rules generally work for small UK limited companies. It isn't tax advice for your specific situation, if you're unsure, check with us or an accountant.