Salary sacrifice arrangements in the United Kingdom
Reviewed by Mellow Editorial Team, HR & payroll content team
Salary sacrifice lets an employee give up part of their contractual cash salary in exchange for a non-cash benefit. The employer pays less National Insurance as a result, and — depending on the benefit — the employee may pay less income tax and National Insurance too.
How salary sacrifice works
The employee and employer formally amend the employment contract to reduce the employee's gross salary. The employer then provides a benefit of equivalent value. Because the salary is lower on paper, both parties calculate tax and National Insurance on the reduced figure.
The key legal point: the salary reduction must be genuine and contractual. A side agreement or informal arrangement does not qualify. HMRC requires that the employee cannot simply switch back to cash on demand — there must be a proper variation of contract, typically with a minimum commitment period.
The employer process, step by step
1. Agree the arrangement in writing.
Draft a salary sacrifice agreement that sets out the reduced salary, the benefit being provided, the start date and the review period. Both parties sign it. This document is the evidence HMRC would ask to see if it ever queries the arrangement.
2. Update the employment contract.
Issue a contract variation letter. The employee's new contractual salary is the reduced figure — not the original salary with a deduction taken off later.
3. Adjust payroll.
Run payroll on the reduced salary from the agreed date. Employer National Insurance at 13.8% and employee National Insurance at 8% (2% above the upper earnings limit) are both calculated on the lower gross. Income tax — at 20%, 40% or 45% depending on the employee's band — is also calculated on the lower figure, subject to the personal allowance of £12,570.
4. Provide and report the benefit.
Deliver the benefit itself (for example, pension contributions, a cycle-to-work scheme or electric vehicle). Some benefits are exempt from income tax and National Insurance altogether; others are not. Pension contributions made under salary sacrifice are employer contributions for HMRC purposes, which removes them from the benefit-in-kind rules entirely. For taxable benefits, report on a P11D by 6 July after the tax year end, or payroll the benefit through PAYE.
5. Continue RTI reporting.
Submit a Full Payment Submission (FPS) to HMRC on or before each payday, as required under Real Time Information rules. The FPS reflects the actual reduced pay, not the original salary.
Which benefits qualify
HMRC distinguishes between "exempt" benefits and those subject to benefit-in-kind tax. Exempt arrangements — where both employer and employee save on National Insurance and the employee saves income tax — include:
- Pension contributions (the most common use case)
- Cycle-to-work schemes
- Ultra-low emission vehicles (subject to their own benefit-in-kind rate)
- Childcare (legacy schemes only; Tax-Free Childcare replaced most new arrangements)
- Annual travel season tickets in some circumstances
Benefits that are not exempt still reduce employer National Insurance but may trigger a benefit-in-kind charge for the employee. Always check the specific HMRC guidance for each benefit type before proceeding.
Auto-enrolment and the pension complication
Salary sacrifice and pension auto-enrolment interact in a way that needs careful handling. When an employee's contractual salary falls as a result of sacrifice, the qualifying earnings figure used to calculate minimum pension contributions also falls. The employer minimum remains 3% and the employee minimum 5% of qualifying earnings — but qualifying earnings are now assessed against the lower salary.
Employers must ensure the sacrifice does not reduce an employee's pay below the National Minimum Wage at any point. This is a common compliance error, particularly for lower-paid workers or those who receive variable pay.
Protecting employees under the Employment Rights Act 2025
The Employment Rights Act 2025 strengthens day-one rights and increases scrutiny of contractual variations. Any salary sacrifice arrangement must be genuinely voluntary — employees cannot be pressured into accepting one, and the variation must meet the standard for a lawful contract change. Where an employee's circumstances change (parental leave, for example), employers should review whether the arrangement remains appropriate and affordable. Statutory family-leave pay is calculated on average weekly earnings, which can be affected if a sacrifice arrangement has been running for some time, so employers should factor this into any assessment before putting an arrangement in place.
---
Run HR and payroll in United Kingdom with Mellow
Mellow brings HR, payroll and 12 AI agents into one platform — built to handle United Kingdom properly, with payroll included, from £4 per employee per month. The AI agents don't just answer questions; they generate contracts, run cost estimates and draft letters for you.
- United Kingdom payroll software
[Start a free trial →](/register)