Dormant Company CT600 Filing: Do You Still Need to File? (Yes — Here's How)
If you have a dormant limited company, you might think you're off the hook for corporation tax returns. No activity, no income, no tax — so no filing needed, right?
Wrong. HMRC still requires dormant companies to file CT600 returns. Missing this obligation leads to penalties, even though you owe zero tax.
This guide explains exactly what dormant means for HMRC, when you need to file, and the quickest way to get it done.
What Makes a Company "Dormant" for HMRC?
Here's where it gets confusing: Companies House and HMRC have different definitions of dormant.
Dormant for Companies House
A company is dormant for Companies House if it has had no significant accounting transactions during the period. The only transactions allowed are:
- Shares issued on incorporation
- Filing fees paid to Companies House
If that's all that happened, you can file dormant accounts at Companies House.
Dormant for HMRC (Corporation Tax)
HMRC considers a company dormant for corporation tax purposes if it:
- Is not carrying on a business and not receiving any income
- Has had no taxable income or chargeable gains during the accounting period
Key difference: A company can be dormant for Companies House but NOT dormant for HMRC. For example, if your company received £10 of bank interest but did nothing else, it's dormant for Companies House but technically active for HMRC.
When Can You Stop Filing CT600s?
You can ask HMRC to make your company dormant for corporation tax, which means they won't expect CT600 returns until you tell them the company has become active again.
To do this:
- Write to HMRC (or call) and tell them your company is dormant
- Provide the date it became dormant
- HMRC will close the corporation tax record
However, if you haven't done this — or if HMRC still considers your company active — you must file CT600 returns for every accounting period. Many directors skip this step and end up with mounting penalties.
Reality check: Most directors with dormant companies haven't notified HMRC. If you're receiving "notice to deliver" letters from HMRC, your company is still on their active list, and you need to file.
The Penalties for Not Filing a Dormant CT600
Even though you owe zero tax, the penalties for not filing are real:
| Time Late | Penalty |
|---|---|
| 1 day late | £100 |
| 3 months late | Another £100 |
| 6 months late | HMRC estimates your tax + 10% penalty on that estimate |
| 12 months late | A further 10% on the estimated tax |
That's right — if you're 12 months late, HMRC will estimate your tax liability (often generously) and charge you 20% of that estimate. Even though you owe nothing. You'll then need to file the actual return to prove the estimate wrong and get the penalty reduced.
It Gets Worse
If you've missed multiple years, the penalties stack. A dormant company that hasn't filed for 3 years could face:
- Year 1: £200 (£100 + £100)
- Year 2: £200
- Year 3: £200
- Plus potential tax estimates and surcharges
That's £600+ in penalties for a company that owes zero tax. We see this constantly — directors who assumed dormant meant "no obligations."
How to Check If HMRC Expects a CT600 From You
Not sure if HMRC considers your company active? Here's how to find out:
- Check your Government Gateway account — log in to HMRC online services and look for any outstanding filing obligations
- Look for "Notice to Deliver" letters — these are formal demands to file a CT600. If you've received one, HMRC expects a return
- Call HMRC's Corporation Tax helpline — 0300 200 3410 (Monday to Friday, 8am to 6pm). They can tell you your company's status
- Check for penalties — if you've already been fined, you definitely need to file
What Goes on a Dormant CT600?
A CT600 for a dormant company is blissfully simple. Nearly everything is zero:
- Turnover: £0
- Trading profits: £0
- Other income: £0
- Chargeable gains: £0
- Total profits: £0
- Corporation tax liability: £0
The return essentially tells HMRC: "My company existed during this period but did absolutely nothing taxable."
What About Bank Interest?
This is the most common gotcha. If your dormant company has a bank account that earned any interest — even 50p — you need to:
- Declare the interest as income on the CT600
- Calculate corporation tax on that interest (19% or 25% depending on thresholds)
- Pay the tax owed
In practice, the tax on a few pounds of interest is negligible, but technically it should be declared. If the amount is genuinely trivial (under £1), many directors and accountants consider it immaterial. But be aware it's a grey area.
Tip: If your dormant company has a bank account, consider switching to a non-interest-bearing account to keep things clean.
Required Attachments
Even a dormant CT600 needs:
- iXBRL-tagged accounts — showing zero activity
- CT600 computation — showing nil tax liability
This is where software helps enormously. Preparing iXBRL accounts manually is impractical — you need software to generate the tagged files.
How to File a Dormant CT600 (Step by Step)
Option 1: Use Taxpipe's Dormant Company Shortcut (Recommended)
Taxpipe has a dedicated feature for dormant company filings. Here's the process:
- Create your Taxpipe account (2 minutes)
- Enter your company details — CRN and UTR
- Select "Dormant Company" when prompted about your company's activity
- Confirm the accounting period — the dates your return covers
- Review the pre-filled return — everything is set to zero
- Submit to HMRC — takes seconds
- Get your IRmark confirmation — you're done
Total time: under 5 minutes. Total cost: £59.
The dormant shortcut skips all the financial input screens since there's nothing to enter. It generates the correct iXBRL accounts automatically and submits everything to HMRC in one click.
Option 2: Use Standard CT600 Software
Any CT600 software will work for a dormant filing — you just enter zeros everywhere. The process takes longer because you'll go through all the standard screens, but the end result is the same.
Option 3: Hire an Accountant
An accountant will typically charge £150-300 to file a nil CT600 for a dormant company. Given that the task takes 5 minutes with the right software, this is difficult to justify unless you have a pre-existing relationship.
Option 4: Tell HMRC Your Company Is Dormant
If your company has been dormant for a while and you don't expect it to become active, you can ask HMRC to mark it as dormant:
- Call HMRC on 0300 200 3410
- Tell them your company name, CRN, and UTR
- Explain the company is dormant and the date it became dormant
- Ask them to make the corporation tax record dormant
Once they do this, you won't need to file CT600 returns until the company becomes active again. But you need to file all outstanding returns first — you can't skip the ones you've already missed.
Filing Dormant CT600s for Multiple Years
If you've fallen behind, you need to file a separate CT600 for each accounting period. You can't bundle multiple years into one return.
For example, if your company has a 31 March year-end and you haven't filed since 2023:
- CT600 for period ending 31 March 2024
- CT600 for period ending 31 March 2025
- CT600 for period ending 31 March 2026 (when due)
With Taxpipe, you can file each one quickly using the dormant shortcut. Just change the accounting period dates for each filing.
Can You Appeal the Penalties?
If you've been penalised for late dormant CT600s, you may be able to appeal. HMRC will consider whether you had a reasonable excuse for filing late. Common arguments:
- ✅ You genuinely didn't know filing was required (sometimes accepted for first-time directors)
- ✅ Serious illness or bereavement
- ✅ HMRC sent correspondence to the wrong address
- ❌ "I forgot" (not accepted)
- ❌ "I didn't think dormant companies needed to file" (HMRC has limited sympathy, but it's worth trying)
- ❌ "My accountant didn't tell me" (you're still responsible)
Our advice: File the outstanding returns first, then appeal the penalties. HMRC is more receptive to appeals when you've brought everything up to date.
Should You Keep Your Dormant Company or Close It?
If you're paying £59 per year just to file nil CT600 returns, it's worth asking whether you should keep the company at all.
Reasons to Keep a Dormant Company
- You plan to trade again in the future
- You want to protect the company name
- The company owns assets (property, intellectual property)
- It has a good credit history you want to preserve
- Striking off would trigger tax charges (e.g., informal distributions)
Reasons to Close It
- You have no intention of trading again
- The annual filing obligations are annoying
- Companies House and HMRC keep sending letters
- The company has no assets and no value
How to Close a Dormant Company
If you decide to close it:
- File all outstanding CT600 returns with HMRC
- File all outstanding accounts with Companies House
- Apply to strike off using form DS01 at Companies House (£33 fee)
- Notify HMRC that the company is being struck off
- Wait for the company to be dissolved (usually 3 months after publication in the Gazette)
Important: File your outstanding returns before applying to strike off. If you have penalties, deal with them first. HMRC can object to the strike-off if you have outstanding obligations.
HMRC's Free Service Is Closing — What Does This Mean for Dormant Companies?
Previously, many directors of dormant companies filed their nil CT600 through HMRC's free service. That's no longer an option after 31 March 2026.
This means dormant company directors face the same choice as everyone else: use commercial software or hire an accountant.
Taxpipe's dormant company shortcut was designed specifically for this situation. At £59 per filing, it's far cheaper than an accountant and takes less than 5 minutes. If you're going to keep your dormant company, it's the most practical option.
Use our corporation tax calculator to confirm your liability is nil before filing — it's free and takes 30 seconds.
Common Questions About Dormant CT600 Filing
Do I need to file a CT600 if I've never traded?
Yes, if HMRC has issued you a "notice to deliver." This happens automatically when you register a company, as HMRC is notified by Companies House. If you told HMRC the company is dormant right from the start, you may not need to file. But if in doubt, file.
What if my dormant company only had bank charges (no interest)?
Bank charges going out of your account don't count as income. If the only transaction was the bank deducting fees, your CT600 is still a nil return. However, the existence of bank charges suggests the account is active, which might complicate your "dormant" status with Companies House.
Can I file a dormant CT600 myself, without software?
Not after March 2026. You need HMRC-recognised software to submit electronically. You can't post a paper CT600 for periods starting after April 2026 either — electronic filing has been mandatory for years.
How often do I need to file?
Every 12 months, aligned with your company's accounting period. Most companies have a 31 March or 31 December year-end, but yours could be different. Check your Companies House filing history to confirm your accounting reference date.
What if I've missed several years of filing?
File them all, starting with the oldest. Use the dormant shortcut for each period. Then either tell HMRC the company is dormant (to avoid future filing) or set a calendar reminder to file annually.
Is £59 per filing worth it for a dormant company?
Consider the alternative: £200+ in penalties for each year you miss, or £150-300 for an accountant to do something that takes 5 minutes. £59 is a small price for compliance.
Summary: What Dormant Company Directors Need to Do
- Check if HMRC expects a CT600 — look for notices to deliver or log into Government Gateway
- File all outstanding returns — use Taxpipe's dormant shortcut for each period (£59 each, under 5 minutes)
- Decide: keep or close? — if keeping, set a yearly reminder to file. If closing, file everything first, then apply to strike off
- Consider notifying HMRC — tell them the company is dormant to avoid future filing obligations (only if you're sure it won't trade again soon)
- Appeal any penalties — once you're up to date, appeal late filing penalties with a reasonable excuse
Don't let a dormant company become an expensive headache. The filing is simple, the cost is minimal, and the penalties for ignoring it are disproportionately harsh.
File your dormant CT600 in under 5 minutes →
Last updated February 2026. This guide covers HMRC dormant company obligations for corporation tax (CT600). Companies House filing requirements (annual accounts, confirmation statement) are separate obligations not covered here.