How salary sacrifice works
Salary sacrifice (sometimes called salary exchange) is an arrangement where you and your employer agree to reduce your contractual salary by a set amount, and your employer provides a non-cash benefit of equivalent value instead. Because your gross salary is lower, you pay less income tax and less National Insurance on it. Your employer also pays less employer NI, which is why many employers are willing to offer the arrangement and sometimes pass the saving back to employees.
Your salary is reduced on paper
You formally agree with your employer to take a lower salary. This is a change to your contract of employment, not simply a deduction from your pay. HMRC requires the arrangement to be a genuine contractual change, not just a reallocation of pay after the fact.
You pay tax and NI on the lower salary
Because your gross salary is lower, your income tax and employee NI are both calculated on the reduced figure. A basic rate taxpayer saves 20% in income tax plus 8% in NI, meaning every £100 sacrificed only costs £72 in take-home pay. A higher rate taxpayer saves 40% tax plus 2% NI, costing just £58.
Your employer saves NI too
Employer NI is 15% on salary above £5,000. When your salary drops, your employer's NI bill also falls. This saving belongs to the employer by default, but many pass it on, particularly for pension sacrifice, where it can be added directly to your pension pot as an additional employer contribution.
You receive the benefit instead
The benefit you receive, a pension contribution, lease car, bicycle, or childcare vouchers, is provided by your employer tax-free or at a favourable rate. The total package value (reduced salary plus benefit) should be the same as or better than your original salary.
Watch out for the minimum wage floor: Your post-sacrifice salary cannot fall below the National Living Wage (£12.21 per hour from April 2025 for workers aged 21 and over). This limits how much lower earners can sacrifice and means cycle to work and childcare schemes have strict maximum limits in practice.
| Scheme | Annual limit | NI saving rate | Key note |
|---|---|---|---|
| Pension | Up to annual allowance (£60,000) | 8% / 2% | Most flexible; no upper limit below annual allowance |
| Electric vehicle | Based on P11D value of car | 8% / 2% | BIK charge still applies; 3% for EVs in 2026/27 |
| Cycle to work | No statutory limit (typically £1,000-£5,000) | 8% / 2% | Must be used mainly for commuting |
| Childcare vouchers | £243/month (basic rate) | 8% / 2% | Closed to new entrants; tax-free childcare now preferred |
What your results mean
The net cost of sacrifice is what the benefit actually costs you after tax and NI savings are applied. For a pension sacrifice, this is the most meaningful figure: it tells you how much your monthly take-home pay falls for every pound you put into your pension. For a basic rate taxpayer, a £500/month pension sacrifice only reduces take-home pay by around £360.
The employer NI saving is worth asking your HR or payroll team about. Not all employers pass this on, but many do for pension sacrifice specifically. If your employer adds their NI saving to your pension, the effective return on your sacrifice improves significantly. On a £10,000 annual sacrifice, the employer NI saving is £1,500.
Note that salary sacrifice reduces your pensionable pay for the purposes of state benefit calculations, statutory maternity and paternity pay, and mortgage affordability assessments (some lenders use basic salary not total package). For most people this is not a significant concern, but it is worth being aware of before committing to a large sacrifice.
Frequently asked questions
No, and the difference matters. A standard employee pension contribution is paid from your net salary and then receives basic rate tax relief added by the pension provider (called relief at source). Salary sacrifice pension contributions are paid from your gross salary before tax, so no tax relief is added separately, the saving comes entirely from paying less tax and NI on a lower salary. Salary sacrifice is generally more efficient because you also save NI on the contribution, which you do not with a standard contribution.
Potentially, in edge cases. State pension entitlement is based on National Insurance contribution years. If salary sacrifice reduces your earnings below the Lower Earnings Limit (£6,396 for 2026/27), you would not accrue an NI qualifying year for state pension purposes. For most full-time workers this is not a concern, as the sacrifice would need to be very large to bring salary below that threshold. However, part-time workers on lower salaries should check their post-sacrifice earnings carefully.
Your employer leases an electric vehicle and you sacrifice salary to cover the monthly lease cost. You pay tax and NI on your reduced salary, saving significantly compared to buying or leasing the car personally. You do still pay a Benefit in Kind (BIK) charge on the car, but the BIK rate for pure electric vehicles is just 3% of the P11D value in 2026/27, rising gradually to 9% by 2028/29. For a £35,000 EV, the BIK charge at 3% is only £1,050 per year, taxed at your marginal rate. The combination of NI savings and low BIK makes EV salary sacrifice one of the most tax-efficient ways to access a new car.
This depends on your employer's scheme rules. Pension sacrifice can usually be changed at any time, subject to your scheme's notice requirements. EV and cycle to work arrangements are typically locked in for the duration of the lease or hire period, as your employer has committed to a contract on your behalf. Childcare vouchers can generally be stopped at any time. HMRC also allows sacrifice arrangements to be unwound if you experience a lifestyle change such as having a child, getting married, or going on maternity leave, even within a fixed-term arrangement.
It can. Many lenders base mortgage affordability on your basic contractual salary, which is the reduced post-sacrifice figure shown on your payslip. If your P60 and payslips show a lower salary due to sacrifice, some lenders will use that lower number. This is particularly relevant if you are sacrificing a large proportion of your salary into a pension or for an EV. Some lenders are more sophisticated and will account for total remuneration, but it is worth confirming with a mortgage broker before maximising a sacrifice arrangement if you are planning to buy property in the near term.
Related calculators
Tax Toolkit UK provides free calculators for guidance purposes only. Results are estimates based on HMRC rates for the 2026/27 tax year. Individual circumstances vary. Always consult a qualified tax adviser before making financial decisions.