Guides
Companies House and HMRC Deadline Guides for Accountants
Companies House and HMRC deadlines drive most of the year in a UK practice. Accounts, confirmation statements, Corporation Tax payments, CT600 returns and Self Assessment all sit on different timetables, and a change to a client's year end or company details moves them. These guides explain how firms keep those dates accurate, sync company data rather than retyping it, manage agent authorisations and remind clients in good time. Remindoo manages the work and reminders; returns are still filed through your usual software. Where rules can change, we link to GOV.UK so you can check the current position.
What this topic covers
- Statutory deadlines
- Companies House sync
- Agent authorisation
- Client reminders
- Tax liabilities view
Companies House and HMRC: common questions
When are private company accounts due at Companies House?
For most private companies, accounts are due nine months after the end of the accounting period. First accounts and changed year ends follow different rules, so check GOV.UK for the specific case.
When is the CT600 due?
The Company Tax Return is usually due 12 months after the end of the accounting period, but the Corporation Tax payment is usually due nine months and one day after it for companies that are not paying in instalments.
What is a confirmation statement?
A confirmation statement (CS01) confirms that the information Companies House holds about a company is up to date. It must be filed at least once every 12 months, within 14 days of the end of the review period.
Why sync with Companies House?
Syncing pulls official company data and filing dates rather than relying on manual entry, which reduces typing errors and helps catch changes such as a new year end.
Does Remindoo file with Companies House or HMRC?
No. Remindoo tracks deadlines, tasks and reminders. Filing is done through your existing software.
Every deadline. Every client. One system.
Start with the workflows that cause the most chasing, then bring leads, AML, proposals and clients into the same calm operating system.
Why a single client record matters
When client details, deadlines, documents and conversations are spread across inboxes and spreadsheets, time goes on searching instead of on client work.
One version of the truth
Everyone sees the same services, contacts, deadlines and notes for each client.
Accurate deadlines
Companies House sync brings in company details and filing dates, reducing manual errors.
Better client service
A full timeline means anyone can answer a client question with the history in front of them.
Secure document sharing
A client portal is safer than sending financial documents as email attachments.
Practical tips from UK practice
- Import companies from Companies House rather than typing details by hand.
- Record every service a client takes, so recurring work is created automatically.
- Add a short note after every important client call.
- Ask clients to upload documents through the portal rather than by email.
Related Remindoo features
Written and reviewed by Waqas Sagar ACA FCCA FMAAT, Chartered Accountant with 18+ years in practice. Founder and MD of Accotax, an ICAEW, ACCA and AAT regulated London practice that has served over 5,000 clients, and founder of Remindoo. Guidance is general; check current GOV.UK and professional body guidance for your firm.
What UK practices say about Remindoo
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“The biggest benefit is having clients, tasks, deadlines, workflows, proposals and communication all organised in one place.”
“During my trial, the team were absolutely amazing. They helped onboard my clients, set up my settings and made sure everything was ready for me to use… they made the whole process completely stress-free.”
“It brings client information, tasks, recurring deadlines, workflows and reminders together in one place, giving us much better visibility across the team.”
