UK PAYE Setup Guide: Register and Run Payroll Correctly in 2026

Missing a deadline with HM Revenue and Customs (HMRC) is one of the fastest ways to rack up penalties for a new business. You don't need to be an accountant to get this right, but you do need to understand the mechanics of Pay As You Earn (PAYE). This system isn't just about deducting tax; it's the legal framework that ensures your employees get paid correctly while keeping the government happy.

If you're hiring your first employee or scaling up in the UK, the process can feel like a maze of acronyms. But once you break it down into registration, software selection, and monthly reporting, it becomes manageable. Here is exactly how to set up your payroll so you never have to worry about compliance again.

Key Takeaways

• You must register as an employer with HMRC before your first payday, not after.
• The Real Time Information (RTI) system requires you to report every payment within two working days.
• National Insurance Contributions (NICs) are a separate calculation from Income Tax and must be tracked individually.
• Paperwork like P45s and P60s are still legally required at specific times, even in a digital age.

When Do You Actually Need to Register?

Many business owners assume they only need to register when they hire their first full-time staff member. That’s a common mistake. Under current UK rules, you are considered an employer if you pay anyone over the Secondary Earnings Threshold (SET). For the 2025/2026 tax year, this threshold is £12,570 per year. If you pay a part-time worker, a casual cleaner, or even a director’s salary that exceeds this amount, you need to be on the PAYE scheme.

There is no grace period. The registration should happen before the first payment is made. If you wait until after you've paid someone, you risk back-dating issues and potential late filing penalties. The process itself is straightforward online via the Government Gateway, but it requires specific details about your company structure, such as your Unique Taxpayer Reference (UTR) and Company Registration Number.

The Step-by-Step Registration Process

Setting up your employer account is the foundation of everything else. Without it, you can't send data to HMRC. Here is the logical flow of what happens during registration:

1. Create a Government Gateway User ID: If you haven't already done this for self-assessment or corporation tax, you'll need to set this up first. It acts as your master login for all HMRC services.
2. Register as an Employer: Log in and select "Employer Services." You will be asked to confirm your business details. Ensure these match your Companies House records exactly. A mismatch here causes delays in approval.
3. Choose Your Reporting Method: You will likely choose "Online" rather than paper forms. This gives you access to the Employment Allowance calculator and other tools directly in your dashboard.
4. Receive Your PAYE Reference: Once approved, HMRC assigns you a unique three-letter office code and a six-digit reference number. Write this down. You’ll need it for every single payroll run.

A critical detail often overlooked is the Employment Allowance. If your total employer NICs bill is under £100,000, you might qualify to reduce your bill by £5,000 annually. During registration, HMRC may ask if you want to claim this. If you’re unsure, it’s safer to opt-in now and adjust later if your headcount grows.

Understanding the Numbers: Tax, NICs, and Deductions

This is where most headaches start. People often confuse Income Tax with National Insurance. They are two different pots of money going to two different places, calculated differently.

Notice the difference in thresholds. Employees don't pay NICs until they earn above £12,570, but employers start paying NICs much earlier, at £9,100. This means if you hire a junior developer at £20,000, you are paying significantly more in employer contributions than the employee is taking home in deductions. Always budget for this extra 13.8% on top of the gross salary.

Running Payroll: The Monthly Cycle

Once registered, the actual work begins. Most small businesses use dedicated payroll software like Xero, QuickBooks, or Deel because manual spreadsheets rarely handle the edge cases of pension auto-enrolment and holiday accrual correctly. However, whether you use software or Excel, the cycle remains the same.

1. Input Hours and Overtime: Start by recording who worked what. Variable pay complicates things, so keep clear logs. 2. Calculate Gross Pay: Add base salary, bonuses, and overtime. 3. Apply Deductions: Subtract Income Tax and Employee NICs based on the current tax codes. 4. Add Employer Costs: Calculate Employer NICs and any pension contributions you owe. 5. Send Data to HMRC: This is the non-negotiable step. You must submit a Full Payment Submission (FPS) via the RTI system.

The Real Time Information (RTI) system changed the game. Previously, you could report quarterly. Now, you must report each individual’s earnings within two working days of paying them. If you pay on the last Friday of the month, you have until the following Tuesday to file. Missing this window triggers automatic penalties unless there is a valid reason for delay.

Year-End Obligations: P45s, P60s, and Yearly Returns

Payroll doesn't stop when the calendar flips. At the end of the tax year (April 5), you have specific document duties.

• P60 Form: Every employee gets one. It summarizes their total gross pay, tax deducted, and NICs paid for the year. They need this for personal tax returns or mortgage applications.
• P45 Form: Issued when an employee leaves. Part 1 goes to HMRC, Part 2 stays with you, and Parts 3 and 4 go to the employee. This tells their next employer how much tax has already been collected.
• Annual Declaration: You must confirm to HMRC that you’ve sent all necessary documents to your staff. This is usually a simple checkbox in your payroll software or online portal.

Forgetting to issue P45s is a frequent source of complaints. If an employee joins a new job without a P45, the new employer may put them on an emergency tax code, causing them to overpay tax temporarily. It creates friction for your departing staff, so treat this as a standard offboarding task.

Common Pitfalls and How to Avoid Them

Even experienced HR managers trip over these specific issues. Keep these in mind to stay compliant.

Misclassifying Workers: Are they an employee or a contractor? If they have control over *how* they work, they might be a contractor (IR35 rules apply). If they are integrated into your team and follow your hours, they are likely an employee. Misclassification leads to back-tax bills and interest charges.

Ignoring Statutory Payments: Maternity pay, paternity pay, and sick pay have their own tax and NIC rules. They aren't always treated the same as regular salary. Check the specific rates for the year you are operating in.

Penalty Accumulation: HMRC uses a points system for late filings. First offense? Warning. Second offense within 24 months? Fine. Third? Bigger fine. Don't let small administrative errors snowball into a significant financial hit.

Frequently Asked Questions