Guide · Updated February 2026
Free CT600 Filing Options After HMRC Closes Its Online Service (April 2026)
From 1 April 2026, HMRC will shut down its free online CT600 filing portal. Over a million UK limited companies that currently file for free will need to find commercial software. This guide covers what is changing, who is affected, and the best options available.
What is happening?
HMRC has announced that its Corporation Tax Online service — the portal most small companies use to file CT600 returns for free — will close on 1 April 2026. After that date, every company filing a corporation tax return will need to use HMRC-recognised commercial software. There is no replacement free service from HMRC.
Who is affected?
Any UK limited company that currently files its CT600 through HMRC's own website. This primarily affects micro-entities and small companies — typically sole-director companies, freelancer limited companies, and small businesses that don't use an accountant or existing tax software. Companies already using software like Xero, FreeAgent, or TaxCalc won't notice any change.
What do I need to file?
A complete filing for a UK limited company involves two submissions:
- CT600 return — submitted to HMRC. This is the corporation tax return itself, including your profit/loss figures and the tax calculation.
- Annual accounts — submitted to Companies House in iXBRL format. Micro-entities use the FRS 105 taxonomy; small companies use FRS 102 Section 1A.
Many companies also need to attach their accounts to the CT600 in iXBRL format. Any software you choose should handle both submissions.
Your options after April 2026
1. Taxentis — from £29/filing
Built specifically for micro-entities and small companies. Search your company on Companies House, enter your profit and loss and balance sheet figures, and Taxentis calculates your corporation tax, generates compliant iXBRL accounts, and submits your CT600 directly to HMRC. No accounting knowledge required. No subscription — pay per filing.
Start your CT600 filing →2. TinyTax
A similar tool aimed at micro-entities. Offers a free tier for basic filings and paid plans for additional features. Has been around longer and has an established user base. Worth comparing if you want a free option, though the free tier may have limitations.
3. TaxCalc
Full-featured tax software used by accountants and businesses. Handles CT600, personal tax, and more. Starts around £70–100/yr. More powerful than you need if you just want to file a simple micro-entity return, but a solid choice if you want a professional tool.
4. Xero / FreeAgent / QuickBooks
Full accounting packages that include CT600 filing as part of a broader suite. Monthly subscriptions typically run £15–40/month. Overkill if you only need to file a CT600 once a year, but useful if you also want bookkeeping, invoicing, and bank reconciliation.
5. Hire an accountant
If you don't want to deal with software at all, a local accountant or online accountancy firm will prepare and file everything for you. Expect to pay £200–500+ per year depending on complexity. This is the hands-off approach, but the most expensive.
What should you do now?
If your accounting period ends before 1 April 2026, you can still use HMRC's online service for that return. But don't wait until the deadline — get set up with a commercial tool before the rush.
For most micro-entity directors, a simple dedicated CT600 tool like Taxentis or TinyTax is the most cost-effective choice. You don't need a full accounting suite to file one return a year.
Ready to file your CT600?
Taxentis makes corporation tax filing simple for UK micro-entities. Search your company, enter your figures, and we handle the rest — tax calculation, iXBRL generation, and direct submission to HMRC.
File your CT600 now