Essential UK payroll deadlines calendar for startups: monthly and annual compliance dates

Understanding the Core UK Payroll Payments

For a founder at a pre-seed to Series B startup, payroll compliance is more than paying your team; it's a high-stakes cycle with unforgiving deadlines. Managing this alongside product development and fundraising can be overwhelming. The risk of costly HMRC penalties, cash-flow shortfalls, and errors from manual tracking is very real. This guide provides a clear UK payroll deadlines calendar for startups in sectors like SaaS, Biotech, and E-commerce, helping you navigate compliance with confidence.

Before diving into dates, it is essential to understand the three distinct payments you will manage. The reality for most pre-seed startups is more pragmatic: getting these three payments correct and on time is the foundation of payroll compliance. These payments are:

• PAYE (Pay As You Earn): This is the income tax you withhold from an employee's salary on behalf of HMRC. The amount is determined by their individual tax code.
• National Insurance (NI): This has two components. You deduct the employee's contribution from their salary. You also pay an additional employer's contribution, which is a direct cost to your business. Both parts are paid together with PAYE in a single transaction to HMRC.
• Workplace Pension Contributions: You must auto-enrol eligible employees into a pension scheme. You deduct the employee's contribution from their pay and add your own employer contribution. This is a separate payment made directly to your chosen pension provider, not to HMRC.

Understanding this distinction is crucial. Grouping the HMRC payment (PAYE and NI) and the separate pension payment is a common error that can lead to compliance issues and inaccurate cash flow forecasting.

The Monthly Payroll Rhythm: Key Dates and Deadlines

Success with payroll compliance comes from understanding its monthly rhythm. It isn't aligned with the calendar month, which often trips up founders new to UK payroll. A UK 'tax month' runs from the 6th of one month to the 5th of the next. All salaries paid within this period are grouped together for tax reporting purposes.

Your key monthly process involves running payroll, reporting the data to HMRC, and making payments. The report you send is called a Full Payment Submission (FPS), which is part of the Real Time Information (RTI) system. You must send the FPS on or before your employees' payment date.

The HMRC Payment Deadline (PAYE & NI)

The critical deadline for your combined PAYE and National Insurance electronic payment to reach HMRC is the 22nd of the month following the end of the tax month. For example, for the tax month ending 5th May, the payment is due by 22nd May. This date is non-negotiable.

Let’s create a visual timeline. Imagine the tax month runs from 6th April to 5th May. You might run payroll on the 25th of April and pay your team on the 28th. The PAYE and NI liabilities calculated for that April payday must be paid to HMRC no later than 22nd May. If the 22nd falls on a weekend or bank holiday, you must ensure the payment clears on the last working day before it.

Pension Contribution Deadlines

Pension deadlines operate on a different schedule. These are set by your provider and outlined in your scheme's payment schedule. A common choice for startups is Nest, whose deadline is also the 22nd of the month following payroll. However, other providers may have different dates. It is essential to confirm this date and build it into your monthly payroll schedule for startups UK. This separation of payments, one to HMRC and one to your pension provider, is a common source of human error when tracked manually.

Annual Payroll Deadlines for UK Startups

While the monthly cycle is your operational heartbeat, the end of the tax year brings a series of crucial, one-off deadlines. The UK tax year ends on 5th April. This date marks the beginning of your year-end reporting duties, which provide a summary of the entire year's payroll to both HMRC and your employees.

Start of the New Tax Year (6th April)

From 6th April, you must apply any new employee tax codes issued by HMRC for the new tax year. Tax codes tell you how much tax-free income an employee gets in a year. They can change due to various factors, so using the latest code is vital for correct deductions. This is often handled automatically by payroll software like Xero or Pento, but it remains your legal responsibility to ensure it happens.

Issuing P60s to Employees (Deadline: 31st May)

Your first major deadline is 31st May, by which you must issue a P60 to every employee who was on your payroll on the last day of the tax year (5th April). The P60 is an essential summary of their total pay and the deductions for the tax year. Employees need it for things like applying for a mortgage or completing a self-assessment tax return.

Reporting Benefits and Expenses (P11D Deadline: 6th July)

Next, you must address any expenses and benefits in kind provided to employees. The deadline to report these to HMRC using the P11D form is 6th July. This includes items like private medical insurance, gym memberships, or a company car. A scenario we repeatedly see is startups overlooking benefits reporting, leading to unexpected liabilities and compliance headaches.

Paying Class 1A National Insurance (Deadline: 22nd July)

Following the P11D submission, the deadline to pay the associated Class 1A National Insurance on these benefits is 22nd July (or 19th July for non-electronic payments). This is an employer-only contribution calculated on the value of most benefits you provide. For many founders, this is an unexpected cost that can impact cash flow if not planned for. These annual tasks are a core part of your startup payroll checklist UK.

The Cost of Missing Payroll Deadlines: HMRC Penalties Explained

Missing deadlines has direct financial consequences that hit your cash runway. HMRC's penalty system is structured to discourage delays in both filing information and making payments.

Penalties for Late Filing (FPS Reports)

For your monthly reporting via the Full Payment Submission (FPS), late filing penalties are charged monthly and are based on your employee count. A fact from GOV.UK states the penalty is £100 for 1-9 employees and £200 for 10-49 employees.

Consider a deeptech startup with 15 employees. If the founder is consumed with an R&D milestone and files the FPS late for three consecutive months, the company faces a £600 penalty (£200 x 3). This is a pure cash burn on a preventable error and a compliance red flag for potential investors during due diligence.

Penalties for Late Payment (PAYE and NI)

For late payments of PAYE and NI, the system has some initial flexibility. HMRC allows one late payment per tax year without a penalty. However, repeated failures trigger penalties calculated as a percentage of the amount that is late. These start at 1% for the second or third default and can rise to 4% for 10 or more defaults in a tax year. While the percentages seem small, for a growing startup with a rising salary bill, they quickly become a significant and unnecessary cost.

A Practical Startup Payroll Checklist UK

Avoiding penalties and cash-flow surprises is not about becoming a payroll expert overnight; it's about building a simple, reliable system. What founders find actually works is focusing on process over heroic last-minute efforts. Here is a practical checklist to make your deadlines bulletproof.

1. Centralise Your Calendar Dates: Create a single HMRC payroll calendar in a shared system. It should include the 5th (tax month end), your chosen payday, the 22nd (HMRC and pension payment due), and all annual deadlines like 31st May and 6th July. Set calendar alerts that trigger 5-7 days before each deadline to give yourself a buffer. Include your RTI and FPS submission dates on that calendar.
2. Separate Your 'Run' and 'Pay' Processes: Create a clear distinction between running your payroll calculations and authorising the payments. Your goal should be to run the payroll at least a week before the employee payday. This gives you and your accountant time to review the figures and correct any errors without pressure.
3. Schedule Payments in Advance: Once the payroll run is confirmed, schedule the bank payments for HMRC and your pension provider immediately. Schedule them for no later than the 20th of the month. This ensures the funds clear by the 22nd, even accounting for potential bank processing delays.
4. Automate with Payroll Software: Use modern accounting software like Xero or dedicated payroll platforms to automate calculations, generate payslips, and handle RTI submissions. This drastically reduces the risk of manual error and saves significant administrative time, freeing you to focus on your business.

Conclusion

Mastering your payroll deadlines for UK startups is a fundamental aspect of financial discipline. By understanding the core payments, internalising the monthly and annual rhythms, and being aware of the penalties, you can transform payroll from a source of anxiety into a predictable business operation. The key is to systemise the process with a clear calendar and internal checks. This simple framework provides the payroll compliance reminders you need, protecting your cash flow and allowing you to focus on what truly matters: building your business. For a broader view, start at the Payroll Overview.

Frequently Asked Questions

Q: What is a Full Payment Submission (FPS)?
A: An FPS is a report you send to HMRC each time you pay your employees, on or before their payday. It details their pay, tax, and National Insurance deductions for the period. It is a core requirement of the Real Time Information (RTI) system and is crucial for staying compliant.

Q: Can I correct a payroll error after I've paid my employees?
A: Yes. You can typically correct an error by updating the employee's year-to-date figures in your next regular FPS. For a significant error in a previous tax year, you may need to submit an Earlier Year Update (EYU) or an additional FPS, so it's best to consult your accountant.

Q: Do I need to run payroll if I'm the only employee of my limited company?
A: Yes, if you are paying yourself a salary as a director, you are an employee for payroll purposes. You must register as an employer with HMRC and operate a PAYE scheme, following the same monthly reporting and payment deadlines as a company with multiple employees.

Q: What happens if the 22nd payment deadline falls on a weekend?
A: If the 22nd of the month is a Saturday, Sunday, or bank holiday, you must ensure your payment reaches HMRC on the last working day *before* the deadline. Banks do not process these payments on non-working days, so planning ahead is essential to avoid an automatic late payment penalty.