UK startup compliance calendar: complete annual deadlines for accounts, tax, payroll, VAT

Understanding the Three Streams of UK Startup Compliance

For UK startup founders, managing statutory compliance often feels like a secondary job, pulling focus from product, sales, and fundraising. The cycle of deadlines for Companies House and HMRC can seem disconnected, creating a constant risk of missed filings and penalties. This guide provides a clear, chronological map of UK startup compliance deadlines, designed to transform a source of anxiety into a manageable, recurring process.

Navigating your obligations begins with understanding who you are reporting to and why. In the UK, compliance is primarily managed by two government bodies: Companies House and HMRC. The two organisations have distinct roles. Companies House governs the legal status and corporate records of your company, while HMRC is responsible for collecting taxes. You can see a year-round roadmap of all filings in our Compliance Checklist.

This separation creates three core streams of compliance that every startup must manage:

1. Corporate Compliance (Companies House): This stream ensures your company’s public record is accurate. The two main filings are the Annual Accounts, which provide a detailed look at your financial performance, and the Confirmation Statement. The "Confirmation Statement is due to Companies House once every 12 months" and serves as a snapshot to confirm that your company details, like director information and shareholder data, are correct.
2. Tax Compliance (HMRC): This involves reporting and paying tax on your company’s profits. The primary filing is the Corporation Tax return (CT600). Crucially, there are two separate deadlines to track. According to HMRC, "The deadline to pay Corporation Tax to HMRC is 9 months and 1 day after the ARD," while "the deadline to file the Corporation Tax return (CT600) with HMRC is 12 months after the ARD." This distinction is crucial for cash flow planning.
3. Payroll Compliance (HMRC): If you have employees, you must manage PAYE (Pay As You Earn). This system requires you to deduct Income Tax and National Insurance from employee salaries and pay it to HMRC. These "PAYE payments to HMRC are due by the 22nd of each month for the previous month's payroll." You can find practical guidance on PAYE payments from payroll specialists.

Nearly all major deadlines are driven by your company's Accounting Reference Date (ARD), which is typically the last day of the month in which your company was incorporated.

The Master UK Startup Compliance Calendar: Key Deadlines

Your ARD is the anchor date for your most significant annual filings, but other statutory obligations follow a fixed national calendar. Here is a breakdown of the key UK startup filing deadlines, separating recurring duties from annual events.

Recurring Monthly and Quarterly Deadlines

• Monthly: PAYE Submission and Payment. Your payment to HMRC for the previous month's payroll is due by the 22nd of every month. Consistent, timely payment is essential to avoid penalties.
• Quarterly: VAT Return and Payment. If your startup is VAT-registered, returns and payments are typically due one month and seven days after the end of your VAT quarter. Remember, "Mandatory VAT registration is required when taxable turnover exceeds £90,000 in a 12-month period." E-commerce businesses should consult specific guidance in the UK E-commerce Compliance checklist.

Annual Deadlines Based on the UK Tax Year

These dates are the same for all UK companies, regardless of their ARD, as they relate to the personal tax year.

• 6th April: The new UK tax year begins. This marks the start of a new period for personal tax and reporting on employee benefits.
• 6th July: This is "The P11D filing deadline for reporting employee expenses and benefits is 6th July." This filing details any 'benefits in kind', like private health insurance or a company car, provided to employees in the previous tax year.
• 22nd July: Following the P11D filing, "The payment deadline for Class 1A National Insurance on benefits is 22nd July."
• 31st January: For company directors, "The Self-Assessment personal tax deadline is 31st January." This relates to their personal income, not the company's.

Annual Deadlines Driven by Your Company's ARD

These critical business tax deadlines are unique to your company’s financial year-end.

• 9 Months after ARD: Annual Accounts Filing. As per Companies House, "The deadline to file Annual Accounts with Companies House is 9 months after the company's Accounting Reference Date (ARD)."
• 9 Months and 1 Day after ARD: Corporation Tax Payment. Your Corporation Tax payment is due to HMRC. Note that you pay this before you formally file the return.
• 12 Months after ARD: Corporation Tax Return (CT600) Filing. Your Corporation Tax return must be filed with HMRC, detailing the profit calculations that support your earlier payment.

For example, a SaaS startup with a 31st March ARD must file its Annual Accounts by 31st December, pay its Corporation Tax by 1st January, and file its CT600 by the following 31st March. In contrast, a Deeptech company with a 31st December ARD must file its accounts by 30th September, pay its tax by 1st October, and file its CT600 by the following 31st December.

Practical Systems for Managing Startup Compliance

Understanding the deadlines is the first step; building a system to manage them is what prevents last-minute panic. Most early-stage startups manage this process using tools like Xero alongside spreadsheets. For tailored guidance, industry-specific compliance notes for SaaS can help align your software with reporting needs.

Solving the Last-Minute Data Scramble

The most common pain point is scrambling for correctly formatted data just before a deadline. The key is to embed compliance into your day-to-day bookkeeping. Within your accounting software, consistently categorise transactions throughout the year. For instance, tag all R&D-related staff costs, contractor fees, and material expenses in Xero as you incur them. This simple habit transforms year-end reporting from a major project into a simple report generation task, making filings for Annual Accounts and R&D tax credits significantly more efficient.

A Special Note on R&D Tax Credits

For Biotech, Deeptech, and many SaaS startups, R&D tax credits are a critical part of the financial strategy. It's a crucial, non-dilutive source of funding that provides a cash rebate on qualifying research and development expenditure. According to the HMRC R&D scheme, "The deadline for R&D Tax Credit claims is two years after the end of the relevant accounting period." While this window seems generous, waiting risks losing the opportunity entirely. Meticulous tracking of R&D costs in your accounting system is essential to maximise your claim. Biotech founders should consult the UK Biotech Regulatory Compliance Timeline for sector-specific details.

Stage-Specific Compliance Priorities

Your statutory compliance priorities naturally evolve as your business grows.

Pre-Seed Stage Focus

At this early stage, the focus is on a solid foundation. Register for PAYE as soon as you hire your first employee and establish disciplined bookkeeping habits in Xero. If you bring on staff, you must follow the UK Pension Auto-Enrolment guide. Ensure the Confirmation Statement is filed on time to maintain good legal standing.

Seed to Series B Stage Focus

As you scale, complexity increases. Your business will likely cross the VAT registration threshold. Employee benefits and P11D reporting become standard annual tasks. A scenario we repeatedly see is founders underestimating the time required for the first full audit of their Annual Accounts, which is often a requirement from investors or due to company size. Proactive management is the key to navigating these growing requirements without disrupting operations.

From Crisis to Process: Systemising Your Compliance

Ultimately, viewing statutory compliance as a predictable system rather than a series of disconnected emergencies is the most effective approach. By mapping these HMRC reporting dates and Companies House requirements into your calendar and embedding data collection into your routine financial operations, compliance becomes a process, not a recurring crisis. For a complete year-round roadmap, refer again to our Compliance Checklist.

Frequently Asked Questions

Q: What happens if I miss a Companies House deadline?
A: Missing the deadline for your Annual Accounts triggers an automatic late filing penalty, starting at £150 and increasing with the delay. For extended delays or a failure to file the Confirmation Statement, Companies House can begin the process to strike the company off the register, putting its legal existence at risk.

Q: What is an Accounting Reference Date (ARD)?
A: The Accounting Reference Date (ARD) is your company's financial year-end. It is automatically set as the last day of the month in which your company was incorporated. All major deadlines for Annual Accounts and Corporation Tax are calculated based on this date, making it the central point of your compliance calendar.

Q: When must my startup register for VAT?
A: You must register for VAT if your VAT-taxable turnover for the previous 12 months was more than £90,000. This is a rolling 12-month period, not a fixed calendar or financial year. You can also register voluntarily before reaching the threshold if it is financially beneficial for your business.

Q: Can I file my own startup accounts and tax returns?
A: While it is legally possible for a director to prepare and file accounts and tax returns, it is generally not recommended. The rules for FRS 102 accounting standards and Corporation Tax are complex. Most startups use an accountant to ensure accuracy, claim all available reliefs like R&D credits, and avoid penalties.