Payroll for Small Businesses: A Complete UK Guide
When Do You Need Payroll?
If you're a sole trader working alone, you don't need payroll — your income goes through Self Assessment. But the moment you take on an employee, payroll becomes a legal requirement.
This includes full-time employees, part-time staff, temporary workers earning above the NI threshold, yourself if you run a limited company, and family members you pay for genuine work.
It does not include genuine self-employed subcontractors. But be careful — HMRC penalises businesses that wrongly classify employees as self-employed.
Setting Up PAYE
Before you pay your first employee, register as an employer with HMRC. This sets up your Pay As You Earn (PAYE) scheme — the system through which you deduct Income Tax and National Insurance from employees' pay and send it to HMRC.
Register online through the HMRC website. You'll need your business details (name, address, UTR number), the date your first employee starts, and how many employees you expect to have. Registration takes up to five working days and provides your Employer PAYE Reference and Accounts Office Reference — you'll need both for submitting payroll reports.
Important: Register before your first payday. If you pay an employee before registration, you'll still owe the PAYE and NI, and you'll have a messy catch-up to do.
PAYE Basics
As the employer, you're responsible for calculating deductions, deducting them from pay, reporting to HMRC in real time, and paying the deductions to HMRC by the deadline.
Most employees in 2025/26 have tax code 1257L, giving a tax-free Personal Allowance of £12,570. Always use the tax code HMRC provides.
National Insurance Contributions
Employee's NI (Class 1 Primary)
- Nothing on the first £242/week (Primary Threshold)
- 8% on earnings between £242 and £967/week
- 2% on earnings above £967/week
Employer's NI (Class 1 Secondary)
- Nothing on the first £96/week (Secondary Threshold)
- 15% on all earnings above £96/week
Employer's NI is the hidden cost of hiring. Someone on £30,000 costs roughly £4,100 extra in employer's NI. Budget for this.
Employment Allowance
Small businesses can reduce employer's NI by up to £10,500 per year, effectively eliminating the cost for many small employers. Claim if your previous year's employer NI was under £100,000.
Real Time Information (RTI)
Every payday, submit a Full Payment Submission (FPS) to HMRC containing each employee's gross pay, tax deducted, NI, student loan deductions, and pension contributions.
If you have no payments in a tax month, submit an Employer Payment Summary (EPS) by the 19th. Failing to submit either triggers penalties.
Auto-Enrolment Pensions
Since 2018, all employers must automatically enrol eligible employees into a workplace pension scheme. This isn't optional — The Pensions Regulator actively enforces it.
Eligible employees meet all three criteria: aged between 22 and State Pension age, earning more than £10,000/year, and working in the UK.
Minimum contributions for 2025/26:
- Employee: 5% of qualifying earnings (includes 1% tax relief)
- Employer: 3% of qualifying earnings
Qualifying earnings are between £6,240 and £50,270. So for an employee earning £30,000, qualifying earnings are £23,760 (£30,000 minus £6,240).
You'll need to select a pension provider before your first employee's enrolment date. NEST (National Employment Savings Trust) is the government-backed scheme — no setup fees, and it must accept all employers. The People's Pension and Smart Pension are also popular choices for small businesses.
Payslip Requirements
Provide payslips on or before payday showing gross pay, net pay, itemised deductions, and hours worked (if pay varies). Paper or electronic — most payroll software generates them automatically.
Key Dates
| Date | What's Due | |------|-----------| | On or before payday | FPS submission | | 19th monthly | EPS (if no payments) | | 22nd monthly | PAYE/NI payment (electronic) | | 5 April | Tax year ends | | 31 May | P60s to employees | | 6 July | P11D forms |
HMRC charges £100/month for late FPS, rising to £400 for four or more months late.
Common Mistakes to Avoid
- Wrong tax code — always use what HMRC provides
- Forgetting employer's NI — it comes from your pocket, not the employee's
- Missing auto-enrolment — The Pensions Regulator fines £50–£10,000/day
- Paying HMRC late — interest accrues from the day after the deadline
- Poor records — keep payroll records for at least three years after the tax year
Get Started with Accounted
Accounted's built-in payroll handles PAYE calculations, RTI submissions, and auto-enrolment pensions alongside your bookkeeping. See our pricing for details. Start your free trial today — no credit card required.
Related Reading
- Tax Guide for Airbnb Hosts: When Rental Income Becomes Taxable
- Tax Implications of Working Abroad as a UK Self-Employed Person
Accounted is built for UK sole traders — bookkeeping, tax, and MTD compliance in one place. See how it works →
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