It's one of the most common questions we hear: "Do I need an accountant to file my CT600?" The honest answer is: it depends. But probably not as much as you think.

Many company directors assume Corporation Tax returns are too complex to handle themselves. In reality, most small companies can file their own CT600 — if they have the right tools and guidance.

Here's how to decide whether you need professional help or can go it alone.

When you DON'T need an accountant

Most small companies can file their own CT600 if they meet these criteria:

Simple company structure

One company (not part of a group)
Straightforward business model (trading, consulting, contracting)
Basic transactions (sales, purchases, expenses, bank interest)
No complex investments or unusual income streams

Clear financial records

Bank statements reconciled and up to date
Income and expense records properly categorized
Receipts and invoices organized and accessible
Basic understanding of what's business vs personal expenses

Time and inclination

Willing to spend 3-6 hours on the process
Comfortable with computers and online forms
Can follow instructions and work methodically
Not stressed by deadlines and form-filling

Typical DIY candidates

Freelancers/contractors operating through limited companies
Small consulting businesses with simple structures
Property companies with buy-to-let portfolios
E-commerce businesses with straightforward operations

When you DO need an accountant

Some situations genuinely require professional help:

Complex business structures

Multiple companies or group structures
Joint ventures or partnership arrangements
International operations or foreign income
Complex shareholding structures

Complicated transactions

R&D tax credit claims (can be worth thousands but complex)
Capital allowances on expensive equipment/vehicles
Significant capital gains from asset disposals
Loan relationships with complex interest calculations
Transfer pricing between related companies

High stakes

Large tax liabilities (£10,000+ Corporation Tax)
HMRC investigations or disputes in progress
Planning to sell the company soon
Applying for significant loans requiring detailed accounts

Personal factors

Lack of time to learn the process properly
Stress around tax matters and deadlines
Previous errors that led to penalties
Preference for professional oversight

Cost comparison

Understanding the real costs helps inform your decision:

DIY approach

Filing software: £50-150 per year
Your time: 3-6 hours annually
Risk: Small penalty risk if errors made

Professional accountant

Small company: £400-800 per year typically
Complex company: £800-2,000+ per year
Additional services: Often bundled (bookkeeping, payroll, advice)

Break-even analysis

If an accountant charges £600 and you value your time at £50/hour, you break even if the CT600 takes more than 12 hours to complete. For most small companies, it takes 3-6 hours.

What's actually involved in CT600 filing

Understanding the process helps assess whether you can handle it:

Information you need

Company details (name, UTR, registration number)
Accounting period dates
Profit and loss figures
Balance sheet figures
Details of any tax already paid

Main CT600 sections

Company information (straightforward form-filling)
Profit and loss (transfer figures from your accounts)
Tax calculation (software usually does this automatically)
Payments and reliefs (enter any tax already paid)

Company accounts preparation

Micro-entity accounts (very simple for small companies)
iXBRL format (software handles this automatically)
Filing with Companies House (often automatic)

Most of this is data entry rather than complex calculation or judgment.

Questions to ask yourself

1. Complexity assessment

Is your business model straightforward?
Are your transactions routine and well-documented?
Do you understand your own financial position?

2. Risk tolerance

Can you afford small penalties if something goes wrong?
Are you comfortable taking responsibility for accuracy?
Do you have time to fix problems if they arise?

3. Time and stress

Do you have 3-6 hours available before the deadline?
Will doing it yourself cause significant stress?
Is your time better spent on business development?

4. Learning preference

Are you interested in understanding how it works?
Do you like having direct control over tax matters?
Will you need to file multiple years going forward?

Software makes the difference

Good filing software transforms CT600 preparation from complex tax form completion to guided data entry:

Plain English questions instead of tax jargon
Automatic calculations for tax and reliefs
Error checking before submission
Direct filing to HMRC and Companies House

At Taxpipe, we've designed our software specifically for company directors who want to file themselves. £59 gets you CT600 preparation, micro-entity accounts, and direct submission — with guidance in plain English throughout.

The honest assessment

For most small companies:

You probably CAN do it yourself with the right software
It's not as complex as you might think
The savings are significant (£300-700 per year)
You'll understand your tax position better

But if your situation is genuinely complex, or you prefer professional oversight, an accountant is worth the cost.

Making the decision

Try this simple test:

Can you explain your company's finances in simple terms?
Are your records organized and up to date?
Do you have time in the month before your deadline?
Are you comfortable with computers and following instructions?

If you answered yes to all four, you can probably file your own CT600.

The worst-case scenario is you start the process and realize you need help — at which point you call an accountant. You haven't lost much besides a few hours.

For many company directors, filing their own CT600 is not only possible but preferable. You save money, understand your tax position better, and maintain control over one of your most important business processes.

The question isn't whether you're capable — it's whether you want to.

File it yourself with Taxpipe

For straightforward small companies, you don't need an accountant. Taxpipe's guided wizard handles the CT600, tax computation, and iXBRL accounts — £59, no subscription, no jargon.

File your CT600 now →

Freelancer? Corporation Tax Guide for Freelancers →

Do I Need an Accountant to File My CT600?