Salary sacrifice saves you more than personal pension contributions because you avoid National Insurance. Here is how it works, the pros and cons, and a worked example.
Salary sacrifice (sometimes called salary exchange) is an arrangement where you agree to give up part of your contractual salary in exchange for your employer paying the equivalent amount into your pension — or towards other benefits like cycle to work schemes or electric car leases.
Because the sacrificed amount never reaches you as salary, neither you nor your employer pay National Insurance on it. And because it reduces your gross pay, you pay less income tax too.
It is a contractual change to your employment terms, not simply a payroll deduction. Your employer must agree to offer it.
With a personal pension contribution, you pay from your net salary. Your provider reclaims 20% tax from HMRC, and you claim additional relief via self-assessment. But you have already paid National Insurance on the full salary — there is no NI saving.
With salary sacrifice, the money goes to your pension before tax and NI are calculated. You save income tax at your marginal rate plus employee National Insurance (8% on earnings between £12,570 and £50,270, 2% above £50,270).
Many employers also pass on their own NI saving (13.8% on the sacrificed amount) to your pension, adding even more to your pot.
Let us compare personal contributions versus salary sacrifice for someone earning £120,000 who wants to put £20,000 into their pension.
Personal contribution: You pay £16,000 out of your net salary. Provider reclaims £4,000 (20%) from HMRC. You claim £4,000 more (extra 20%) via self-assessment. Total in pension: £20,000. Total cost to you: £12,000.
Salary sacrifice: Your gross salary drops from £120,000 to £100,000. Employer pays £20,000 into your pension. Income tax saving: £8,000 + £4,000 (personal allowance restored) = £12,000. NI saving: £400 (2% on £20k). Total in pension: £20,000. Total cost to you: £7,600.
Salary sacrifice saves you an extra £4,400 per year.
Higher effective tax relief: You save NI on top of income tax, and possibly benefit from employer NI pass-through.
Personal allowance restoration: If your salary is between £100,000 and £125,140, sacrifice reduces your adjusted net income — restoring some or all of your £12,570 personal allowance.
Automatic — no self-assessment needed: The tax saving happens through payroll. No need to file a self-assessment return solely to claim pension relief.
No net pay anomaly: Unlike personal contributions through net pay schemes, salary sacrifice always provides the full benefit regardless of your tax band.
Lower gross salary on paper: Your contractual salary is reduced. This can affect mortgage applications (lenders look at gross salary), statutory maternity/paternity pay, life insurance based on salary multiples, and redundancy pay.
Not all employers offer it: Salary sacrifice requires employer agreement and setup. Smaller employers may not provide it.
Minimum wage floor: Your employer cannot sacrifice your salary below the National Minimum Wage. For most high earners this is not a concern, but it limits how much lower-paid employees can sacrifice.
Less flexibility: A salary sacrifice arrangement is a contractual change. You typically cannot adjust it more than once or twice per year (at annual review windows).
Step 1: Ask your HR or payroll department if salary sacrifice for pension is available. Most large and medium employers offer it.
Step 2: Decide how much to sacrifice. Use our strategies tool to model the optimal amount based on your income and the 60% trap window.
Step 3: Sign the salary sacrifice agreement — this formally amends your employment contract.
Step 4: Check your next payslip. You should see a lower gross salary, lower tax, lower NI, and a higher employer pension contribution.
For anyone earning above £50,270 (the higher rate threshold), salary sacrifice is almost always more beneficial than personal contributions because of the NI saving. For earners in the £100k–£125k 60% trap band, it is significantly more beneficial.
The only scenario where personal contributions may be preferable is if you need to maintain a higher gross salary figure for mortgage or other applications in the near term. In that case, you might make personal contributions temporarily and switch to salary sacrifice later.