The Complete Guide to Workplace Pensions and Auto-Enrolment for Employers

Auto-enrolment is not a suggestion. It's not something you can "look into when things slow down." Every UK employer—whether you're a sole trader or have 50 staff—has to offer a workplace pension and automatically enrol eligible employees into it. The Pensions Regulator enforces it. Getting it wrong costs money. Getting it right is straightforward if you know what you're doing.

This guide covers everything you need to know: who gets enrolled, what you have to contribute, how to set it up, and where the most common mistakes happen.

What auto-enrolment actually is

Auto-enrolment is the legal requirement to automatically put eligible workers into a qualifying workplace pension scheme and contribute to it. The word "automatic" is key—employees don't opt in. They're enrolled by default, though they can opt out if they choose.

Before this was the law, most workers had no pension savings because nobody forces you to save. The government decided to flip the default: instead of "pension unless you ask for one," it became "pension unless you actively say no." Behavioural economics suggests this works. The evidence backs it up.

Every eligible worker, on every pay run, must be assessed. Their status—and therefore your obligations—can change month to month as their earnings move above or below the threshold.

Who gets enrolled, and who doesn't

Not everyone who works for you gets auto-enrolled. The rules depend on age and earnings.

Eligible jobholders (these must be enrolled):

Aged 22 to State Pension age
Earning above the earnings trigger (set by the government each year)
Working in the UK

Non-eligible jobholders (optional enrolment; you contribute if they opt in):

Aged 16–74
Earning above the Lower Earnings Limit but below the trigger, OR
Aged 16–21 or above State Pension age but earning above the trigger

Entitled workers (can ask to join, but no employer contribution required):

Earning below the Lower Earnings Limit

The tricky bit: you must reassess every employee on every pay run. Someone who wasn't eligible in January might be in February if their hours increased. This is the mistake most employers make—they assess once and assume nothing changes.

Choosing a pension scheme

Before you enrol anyone, you need a scheme. It must meet minimum standards and be registered with The Pensions Regulator. Here are your main options:

NEST (National Employment Savings Trust) — The government-backed scheme. NEST must accept any employer. Simple, transparent, good for small businesses. Contributions go straight from payroll, no faff.

Multi-employer schemes — Providers like The People's Pension, NOW: Pensions, Smart Pension. Designed for auto-enrolment from the ground up. More investment choices than NEST, still straightforward to administer.

Insurance company schemes — Aviva, Scottish Widows, Royal London, and others. More investment options, more features. Can be overkill for a five-person firm, but not wrong if you want them.

Self-invested personal pensions (SIPPs) — Possible but uncommon for auto-enrolment. Usually used by higher-earning businesses where staff want more control.

When you're choosing, focus on:

Setup costs (does the provider charge the employer or the members?)
Ongoing admin burden
Whether it integrates with your payroll software (this matters more than you think)
Communication and reporting tools

The integration point is critical. If your pension provider and payroll system don't talk to each other, you're calculating and submitting contributions manually. That's where errors creep in.

How much do you have to contribute?

Minimum total contribution: 8% of "qualifying earnings."

Who pays what:

Employer: 3% minimum
Employee: 5% minimum

"Qualifying earnings" means earnings between the Lower Earnings Limit and the Upper Earnings Limit. Anything below or above gets ignored for contribution purposes.

So if an employee earns £2,000 in a month and £1,200 of that falls within the qualifying range, you calculate the 3% on £1,200, not £2,000.

Some employers use "contributions on total earnings from the first pound" instead—a different approach that can satisfy the rules. Check with your pension provider or an adviser if you want to explore this.

Setting up and running the scheme

Setting up a workplace pension scheme involves legal steps, but they're well-trodden:

Choose your scheme (covered above)
Register with The Pensions Regulator (your provider will guide you through this)
Create a workplace pension policy (what you're offering, how people access it, what happens if they leave)
Assess your current workforce — who's eligible right now?
Enrol eligible workers — within the rules (new starters within three months; existing staff at the staging date)
Write to them — within six weeks, confirming enrolment and their right to opt out
Start deductions — from the next pay run
Declare compliance with The Pensions Regulator within five months

You can postpone enrolment by up to three months (useful for new starters during their probation). After postponement, you must enrol them without further delay.

Once everything is running, the cycle is straightforward: assess on every pay run, calculate contributions, submit to the provider, track who's opted out, and re-enrol opt-outs every three years.

Pension contributions and payroll

This is where payroll software earns its keep. On every pay run:

Calculate qualifying earnings for the employee
Apply the contribution rate
Deduct the employee's portion (from gross pay if relief at source; from net if net pay arrangement)
Calculate and set aside the employer contribution
Submit both to the pension provider by the deadline

Relief at source — Employee contribution is deducted after tax. The pension provider claims basic rate tax relief from HMRC and adds it to the member's pot. Most small-business auto-enrolment schemes use this.

Net pay arrangement — Employee contribution is deducted before tax is calculated. Tax relief is automatic because taxable income is lower. More complex to administer; less common for auto-enrolment.

If your payroll software doesn't automatically handle assessments and contribution calculations, you're manually checking eligibility and doing spreadsheet math. That's how errors happen.

Common mistakes that cost money

Not assessing every pay run. You must look at every employee every month. If someone's hours increase, they might become eligible. If someone goes on unpaid leave, they might drop out. You can't just assess when they join.

Late enrolment. If an employee should have been enrolled in month two but you enrol them in month three, you owe backdated contributions. The Pensions Regulator issues compliance notices and penalties for this.

Wrong contribution calculation. Using total earnings instead of qualifying earnings. Using the wrong rate. Not accounting for the thresholds. These errors add up.

Missing the communications window. You must write to employees within six weeks of enrolment, confirming the scheme, contribution rates, and their right to opt out. Missing this deadline is a breach even if everything else is correct.

Encouraging opt-outs. It's illegal to persuade or incentivise someone to opt out. Even saying "most people don't stay in" counts. Present it neutrally, and then drop it.

Not tracking re-enrolment dates. Every three years, you re-enrol anyone who previously opted out. If you miss the window, you're in breach.

These aren't small slip-ups. The Pensions Regulator takes them seriously.

The Pensions Regulator: what they can do

The Pensions Regulator has real teeth. They can:

Issue a compliance notice telling you to fix something by a specific date
Issue a fixed penalty notice (currently £400 per worker, per year of breach)
Issue escalating daily penalties (£50 to £10,000 per day depending on employer size and severity)
Prosecute for willful non-compliance (criminal offence)

They're generally reasonable if you've made a genuine mistake and are correcting it. But if you ignore them or keep making the same mistakes, expect penalties.

You must file a Declaration of Compliance within five months of your duties starting, and every three years at re-enrolment.

Integration with payroll and HR

The admin burden drops dramatically when your pension scheme integrates with your payroll and HR system. Look for:

Automatic eligibility assessment on every pay run
Contribution calculations built in
Pension data export in your provider's format
Opt-out tracking and re-enrolment reminders
Pre-written letters that meet the legal requirements

When pension admin, payroll, tax codes, and National Insurance all sit in one system, you're looking at the same employee record every time. No data gets lost between spreadsheets. Errors become rare.

Related schemes like salary sacrifice (which can apply to pensions and cycle-to-work arrangements) also integrate more cleanly when everything's in one place.

Frequently Asked Questions

Q: What's the difference between auto-enrolment and a personal pension? A: Auto-enrolment is your legal duty to offer and contribute to a workplace scheme. A personal pension is an individual product. You can't satisfy auto-enrolment with a personal pension; you need a workplace scheme (NEST, a multi-employer scheme, or your own insured scheme).

Q: Can I defer auto-enrolment when I first become an employer? A: You can postpone enrolment by up to three months from the date you become an employer (your "duties start date"). After that postponement expires, you must enrol eligible workers without further delay.

Q: What happens if an employee opts out? A: They leave the scheme. If they opt out within one month of enrolment, any contributions you've already deducted must be refunded. You don't have to re-enrol them immediately, but you do have to re-enrol them every three years (the cyclical re-enrolment duty).

Q: Do I have to make contributions for employees earning below the trigger? A: Only if they ask to join. Non-eligible jobholders earning above the Lower Earnings Limit can request to be enrolled, and then you must contribute. Entitled workers (below the Lower Earnings Limit) can ask to join, but you're not obligated to contribute to their scheme.

Q: Can I use a SIPP instead of a workplace scheme? A: No. A SIPP is a personal product. Auto-enrolment requires a workplace scheme registered with The Pensions Regulator. NEST, multi-employer schemes, and insured workplace schemes all work. A SIPP doesn't.

Q: How often do I need to file with The Pensions Regulator? A: You file a Declaration of Compliance within five months of your duties start date, then every three years at re-enrolment (if you're using cyclical re-enrolment). If you use an alternative staging date strategy, timings change—check with your provider.

Q: What if I make a mistake with contributions? A: Report it to your pension provider and The Pensions Regulator. If the mistake is unintentional and you're correcting it, penalties are usually lower than if you ignore it. Get professional advice—an accountant or pensions consultant can help you make the correction properly.

Q: Is it ever legal to encourage someone to opt out? A: No. You can provide information about opting out (employees have a right to do so), but encouraging, inducing, or incentivizing them is a criminal offence. Even casual remarks can count.

Key takeaways

Auto-enrolment is permanent, non-negotiable, and here to stay. The rules are clear. The enforcement is real. But so is the support:

Choose a scheme that integrates with your payroll software. This eliminates the biggest source of errors.
Assess on every pay run. Someone's status can change month to month.
Enrol promptly. Late enrolment triggers backdated contributions and penalties.
Calculate correctly. Use qualifying earnings, apply the right rates, and double-check.
Communicate. The letters and notifications are not optional; they're legal requirements.
Re-enrol every three years. Mark the date in your calendar now.
When in doubt, ask. Your pension provider, accountant, or The Pensions Regulator can clarify.

Getting auto-enrolment right from the start is far simpler than sorting out years of mistakes later. If you're setting up a workplace pension scheme for the first time, a step-by-step guide to setting one up walks you through the process.