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What is a CT600?

  • 4 min read
  • Last updated 18 Jun 2024

Navigating the maze that is business taxes can be overwhelming. Seriously, what is a CT600?

With so many forms to keep track of, it’s so easy to get lost in the process. Luckily for you, TaxScouts revels in all things tax and tax forms. We’re here to simplify things for you.

We’ll ask again… what is a CT600?

So, what’s a CT600 form? Put simply, it’s the form that tells HMRC how much corporation tax your company owes. And it’s just one of the documents that forms your annual company tax return.

Let’s take a closer look at who needs to submit a CT600 and how you can go about doing it correctly.

Who needs to complete a CT600?

All companies registered in the UK with Companies House need to file a CT600 annually. Why? So that HMRC knows how much corporation tax you’ll need to pay on your profits. 

This includes limited companies, public limited companies (PLCs), and certain clubs, societies and associations that are liable for corporation tax. 

Essentially, if your company is subject to corporation tax, you’ll need to complete and submit a CT600 form each year.

Not sure whether you need to or not?

No worries, get tax advice from a professional accredited accountant about your situation. They’ll help you with all things company tax. 30 minutes, 1-1, 100% remote.

When do I need to submit it by?

This is where things can get a little more complicated, so let’s break it down.

Every company has its own CT600 form deadline. Since the CT600 forms part of your company tax return, your CT600 is essentially due on the same date as your company tax return.

This will coincide with the end of your accounting period

For example, if your financial year ends on 31 March, that’s the end of your accounting period. You’ll need to submit you company tax return (including the CT600) within 12 months of this date.

You can learn more about the corporation tax due date here. Use our guide as a calculator to find out when your corporation tax and company tax return are due.

Is there a penalty if I file my CT600 late?

Since the CT600 forms part of your company tax return, you’ll face the same late filing penalties as you would for your tax return. And this can come with some pretty hefty fees 😰.

If you’re even just 1 day late with your company tax return, you’ll get hit with a £100 penalty. Let that slide for another 3 months and you’ll be charged an extra £100 on top. 

If you still don’t file 6 months down the line, HMRC starts estimating your tax bill and adds a penalty of 10%.

Let’s imagine 12 months have passed. Guess what? Another 10% penalty is added. So, to avoid these headaches, make sure you get your CT600 in on time!

Avoid penalties with professional help

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What’s the difference between a CT600 and a CT603

It’s pretty easy to get the CT600 and CT603 mixed up – they are similar numbers after all! But they both serve different purposes when it comes to your company tax return.

The CT603 is simply a notice from HMRC to request the filing of your CT600 (corporation tax for your company tax return).

It’s HMRC’s way of saying: “It’s time to get your tax affairs in order.” So, when you receive a CT603 notice, it’s time to prepare your CT600 form for submission.

How to submit Corporation Tax for Company Tax Return

Looking for a helping hand to submit your CT600 form? Follow these simple steps.

  • Step 1: Gather your financial information. Before you start filling out the CT600 form, you’ll need to make sure you have the following to hand:
    • Income statements
    • Balance sheets
    • Records of expenses
    • Details of any allowances and reliefs
    • Previous company tax returns (if applicable)
  • Step 2: Access the CT600 form. Visit the HMRC website or use compatible accounting software.
  • Step 3: Complete the form. We recommend you have an accountant do this for you. Let an accredited accountant sort it all for you, for less. Get started here.
  • Step 4: Review and submit. Check all of the information is correct before submitting. You don’t want to underpay corporation tax as HMRC will charge you interest.
  • Step 5: Pay your corporation tax. Your bill will be due in full or in installments and you can pay it online.

You can learn more about how to pay corporation tax here.

Or, of course, you can always just use TaxScouts.

How can TaxScouts help?

Let us sort your year-end accounts and corporate tax return without the stress. Our accredited accountants can take care of the CT600 form (and your year-end accounts) for you for a one-off, affordable price.

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