Salary Sacrifice Pension or ISA First? The 2026/27 Decision Framework
Salary sacrifice into your pension saves Income Tax and National Insurance immediately. An ISA gives you tax-free access at any age. Here's how to decide which should get your next spare pound in 2026/27.
Why Salary Sacrifice Beats a Normal Pension Contribution
Salary Sacrifice Calculator
Calculate how much tax and National Insurance you save by making salary sacrifice contributions to a pension, cycle to work scheme or EV car scheme.
Salary sacrifice calculatorWhen you contribute to a pension from your take-home pay, you get Income Tax relief but National Insurance has already been deducted from your salary before the contribution is made. Salary sacrifice restructures your contract so the pension contribution comes out of your gross salary before either tax is calculated:
| Contribution method | Income Tax saved | Employee NI saved | Combined saving (basic rate) |
|---|---|---|---|
| Normal contribution (net pay/relief at source) | 20% | 0% | 20% |
| Salary sacrifice | 20% | 8% | 28% |
For a higher-rate (40%) taxpayer, salary sacrifice saves 40% Income Tax plus 2% NI (above the upper earnings limit) — still a meaningful uplift over a normal contribution.
Worked Example: £200/Month Extra
| Method | Employee cost after tax/NI relief | Amount reaching pension (basic rate example) |
|---|---|---|
| Normal net contribution | £160 (after 20% relief added back) | £200 |
| Salary sacrifice | £144 (20% tax + 8% NI both saved) | £200 (plus any employer NI saving passed on) |
The pension receives the same £200 either way, but salary sacrifice costs you less take-home pay to achieve it — and many employers add some or all of their own 15% employer NI saving on top, meaning more than £200 can end up in the pension for the same net cost.
What an ISA Offers That Salary Sacrifice Cannot
| Feature | Pension (salary sacrifice) | ISA |
|---|---|---|
| Access | Locked until age 57 (2028+) | Accessible any time, any reason |
| Tax on growth | Tax-free growth, but income taxed on withdrawal (25% usually tax-free) | Entirely tax-free, no tax on withdrawal |
| NI saving | Yes | No |
| Effect on mortgage affordability | Can reduce assessed gross salary | No effect |
| Effect on means-tested benefits/thresholds | Reduces adjusted net income (can restore Child Benefit, Personal Allowance) | No direct effect |
The £100,000–£125,140 Trap and the Child Benefit Charge
Two specific income bands make salary sacrifice unusually valuable beyond the headline tax/NI saving:
- £100,000–£125,140: your Personal Allowance is withdrawn at £1 for every £2 earned, creating an effective marginal rate of 60% in this band. Salary sacrifice that brings your adjusted net income back under £100,000 restores the allowance entirely.
- £60,000–£80,000 with Child Benefit claimed: the High Income Child Benefit Charge claws back Child Benefit on a sliding scale, fully removed by £80,000. Salary sacrifice reduces adjusted net income and can preserve some or all of the benefit.
An ISA contribution has no effect on either calculation, because ISA contributions are made from post-tax income and don't reduce adjusted net income.
Decision Framework
- Money you won't need before 57: favour salary sacrifice, especially if you're in the £100k–£125,140 band or losing Child Benefit.
- Money you might need sooner (house deposit, emergency buffer beyond existing savings, medium-term goals): use an ISA.
- Planning a mortgage application soon: check with a broker whether reducing your contractual salary via sacrifice affects the amount you can borrow, before increasing sacrifice significantly.
- Most households: use salary sacrifice up to at least any employer-matched level, then split additional saving between further sacrifice and an ISA based on how soon the money might be needed.
Frequently asked questions
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