Salary Sacrifice and Auto-Enrolment: What Employers Must Know

Salary sacrifice pension schemes and auto-enrolment are two of the most important pieces of the UK workplace pension landscape — and the interaction between them is an area where employers regularly get into difficulty. The Pensions Regulator (TPR) is unambiguous: salary sacrifice is an acceptable method of meeting auto-enrolment duties, but only if done correctly. Get the mechanics wrong and you could face compliance notices, penalty notices, or worse.

I’ve spent over two decades helping employers navigate benefits compliance, and the salary sacrifice / auto-enrolment intersection remains one of the most frequently misunderstood areas. Here’s what you need to know.

How auto-enrolment works: the basics

Under the Pensions Act 2008 (as amended), every UK employer must automatically enrol eligible jobholders into a qualifying workplace pension scheme. The key parameters for 2025-26 are:

Parameter	Value
Eligible jobholders	Aged 22 to State Pension age, earning above £10,000 p.a.
Qualifying earnings band	£6,240 to £50,270
Minimum total contribution	8% of qualifying earnings
Minimum employer contribution	3% of qualifying earnings
Minimum employee contribution	5% of qualifying earnings

These thresholds have been frozen for several years and are expected to remain unchanged for 2025-26, though the government reviews them annually.

How salary sacrifice fits in

Under a salary sacrifice arrangement (sometimes called “smart pension” or “salary exchange”), the employee agrees to a contractual reduction in their gross salary, and the employer pays the equivalent amount into the pension scheme as an employer contribution. The entire contribution is technically an employer contribution — there is no employee contribution as such.

This is the source of both the tax efficiency and the compliance complexity.

The tax advantage

When contributions are made via salary sacrifice:

• The employee’s gross salary is reduced, so they pay less income tax and employee NI on the sacrificed amount
• The employer pays less employer NI on the reduced salary (15% saving in 2025-26)
• The full sacrifice amount goes into the pension — there’s no income tax or NI deduction to reduce it

Compare this with a traditional net pay arrangement where the employee contribution comes out of net pay (or out of pre-tax pay under net pay arrangement rules). Salary sacrifice is almost always more tax-efficient for both parties.

Why TPR accepts salary sacrifice

TPR has confirmed that salary sacrifice is an acceptable way to meet auto-enrolment duties. Their position, set out in detailed guidance, is that what matters is the outcome — that sufficient contributions reach the pension scheme — not the mechanism by which they get there.

Under salary sacrifice, the combined employer contribution (original employer share plus the sacrificed amount) must meet or exceed the total 8% minimum contribution on qualifying earnings. Since the entire amount is paid by the employer, this is a single calculation.

The five critical compliance points

1. Qualifying earnings must be calculated on the pre-sacrifice salary

This is the most important technical point. When determining whether an employee meets the earnings trigger for auto-enrolment (£10,000) and when calculating qualifying earnings for minimum contribution purposes, you must use the original, pre-sacrifice salary — not the reduced post-sacrifice salary.

TPR is explicit on this. If you use the post-sacrifice salary, you will understate the employee’s qualifying earnings and potentially pay insufficient contributions. This is a compliance breach.

Example: An employee earns £30,000 and sacrifices £2,000 into pension.

• Correct qualifying earnings: £30,000 - £6,240 = £23,760 (capped at £50,270 - £6,240 = £44,030)
• Minimum 8% contribution: £23,760 × 8% = £1,900.80
• Incorrect qualifying earnings (using post-sacrifice salary): £28,000 - £6,240 = £21,760
• Incorrect minimum contribution: £21,760 × 8% = £1,740.80

Using the post-sacrifice salary understates the required contribution by £160 per year in this example. Across a workforce, the shortfall adds up.

2. The employer contribution must meet the total minimum

Under salary sacrifice, the entire pension contribution is technically an employer contribution. The employer must ensure this total contribution meets or exceeds the combined minimum of 8% of qualifying earnings (calculated on the pre-sacrifice salary, as above).

Most salary sacrifice schemes are set up so the employer contributes their original share (typically 3% or more) plus the sacrificed amount (equivalent to what was the employee’s 5% share). As long as the combined figure meets the 8% minimum, you’re compliant.

Where employers run into problems is when:

• The sacrifice amount is set as a fixed cash amount rather than a percentage, and salary changes cause it to fall below the minimum
• The employer contribution percentage is calculated on the post-sacrifice salary rather than the original salary
• Rounding or payroll system errors cause marginal shortfalls that accumulate over time

3. Opt-out rights must be preserved

Employees who are auto-enrolled have a statutory right to opt out within one month of enrolment. Under a salary sacrifice arrangement, opting out means the salary sacrifice must be reversed — the employee’s gross salary must be restored to its pre-sacrifice level.

This creates an administrative requirement: your payroll system must be able to handle the reversal cleanly, including recalculating income tax and NI for the opt-out period. Most modern payroll systems handle this, but it’s worth testing the process.

Additionally, employees who have opted out must be re-enrolled approximately every three years (the “cyclical re-enrolment” duty). At each re-enrolment point, the salary sacrifice arrangement must be offered again, and the opt-out process must be available.

4. Contractual documentation must be correct

A salary sacrifice arrangement requires a variation to the employee’s contract of employment. The contract must clearly state:

• The employee’s original salary (before sacrifice)
• The reduced salary (after sacrifice)
• The amount being sacrificed and how it is calculated (fixed amount or percentage)
• That the sacrifice is in exchange for the employer making an equivalent pension contribution
• The employee’s right to opt out of the sacrifice arrangement
• The circumstances in which the sacrifice will be reviewed (typically annually, or on certain life events such as maternity leave)

Without proper contractual documentation, HMRC could argue that the arrangement is not a genuine salary sacrifice and deny the NI advantages. TPR could also take the view that the auto-enrolment duties have not been properly discharged.

5. Life events and salary sacrifice breaks

Most salary sacrifice arrangements include “life event” provisions that allow employees to opt out or reduce their sacrifice when their circumstances change — for example, maternity leave, long-term sickness, or a significant reduction in income.

During these periods, you must continue to meet your auto-enrolment duties. If the salary sacrifice is suspended during maternity leave, the employer must still ensure minimum pension contributions are being made. This may mean the employer covers the full 8% during the leave period, depending on how your scheme is structured.

This is an area where clear policy documentation and payroll system configuration are essential. Ad hoc or manual handling of these cases is a recipe for compliance errors.

What happens if you get it wrong

TPR has a range of enforcement powers:

• Compliance notices requiring the employer to take specific corrective action
• Fixed penalty notices of £400
• Escalating penalty notices ranging from £50/day for micro-employers to £10,000/day for employers with 500+ workers
• Prohibited recruitment conduct penalties if the employer tries to discourage pension membership

In practice, TPR tends to work with employers to correct issues before escalating to penalties. But repeated or deliberate non-compliance will result in enforcement action. The reputational damage of being named as non-compliant can also be significant.

Practical tips for getting it right

1. Audit your qualifying earnings calculation — confirm your payroll system uses the pre-sacrifice salary, not the post-sacrifice figure
2. Review contribution levels annually — ensure the combined employer contribution (including sacrificed amount) meets the 8% minimum on current qualifying earnings
3. Test your opt-out process — run a dummy opt-out through payroll to verify the salary restoration and NI recalculation work correctly
4. Document everything — contract variations, scheme rules, and policy documents should be up to date and accessible
5. Model the numbers — use our Employer Calculator to see the employer NI savings from salary sacrifice pension contributions across your workforce

For detailed pension salary sacrifice calculations, see our Pension Salary Sacrifice Calculator guide. For a broader overview, visit the Salary Sacrifice Calculator page.

Calculate your pension salary sacrifice savings →

Frequently asked questions

Is salary sacrifice an acceptable way to meet auto-enrolment duties?

Yes. The Pensions Regulator has confirmed that salary sacrifice (also known as salary exchange or smart pension) is an acceptable method of meeting auto-enrolment duties. The key requirement is that sufficient contributions reach the pension scheme — at least 8% of qualifying earnings, of which at least 3% must be the employer’s own contribution (not from the sacrifice).

Do I calculate qualifying earnings on the pre-sacrifice or post-sacrifice salary?

Always use the pre-sacrifice salary. TPR is explicit that qualifying earnings for auto-enrolment purposes must be calculated on the employee’s original contractual salary before any salary sacrifice reduction. Using the post-sacrifice figure will understate qualifying earnings and may result in insufficient contributions.

What happens when an employee opts out of salary sacrifice pension?

The salary sacrifice must be reversed and the employee’s gross salary restored to its pre-sacrifice level. The opt-out right applies within the first month of auto-enrolment. Your payroll system must handle the salary restoration and recalculate income tax and NI for the opt-out period. The employee must be re-enrolled approximately every three years under the cyclical re-enrolment duty.

How does salary sacrifice pension work during maternity leave?

During paid maternity leave, the employee’s contractual benefits — including salary sacrifice pension arrangements — generally continue, although the sacrifice element may be adjusted or suspended depending on the level of maternity pay. The employer must continue to meet auto-enrolment minimum contribution duties throughout the leave period. Clear policy documentation is essential to ensure correct handling.

Can TPR penalise employers for salary sacrifice compliance errors?

Yes. TPR has a range of enforcement powers including compliance notices, fixed penalties of £400, and escalating daily penalties from £50 to £10,000 depending on employer size. In practice, TPR usually works with employers to correct issues before escalating, but repeated or deliberate non-compliance will result in formal enforcement action.