Every £100 Into Your Workplace Pension Costs You £72. The Same £100 in a SIPP Costs You £80. The Choice Is Not Close.

Salary sacrifice works because your employer pays the salary you give up straight into the pension before Income Tax or National Insurance are calculated. The GOV.UK guide on workplace pensions puts it in plain terms: "you give up part of your salary and your employer pays this straight into your pension… this will mean you and your employer pay less tax and National Insurance."

Do the maths on the current 2026/27 rates. A basic-rate payer gives up £100 of gross salary and pays 20% Income Tax plus 8% employee National Insurance on it — so £100 in the pot costs £72 of take-home pay. A SIPP only recovers the tax: you pay in £80 and HMRC tops it up to £100. The same £100 costs £80.

Make it a person rather than a percentage. Sacrifice £200 a month and it costs you £144 of take-home pay. To get the same £200 into a SIPP you pay £160. That is £16 a month — £192 a year — for life, banked before any fund is chosen and before any market opens.

That £8 in every £100 is not investment return. It is not a forecast, a valuation, or a bet on the direction of equities. It is a guaranteed saving you bank on day one, whatever markets do next. In a year when the 10-year gilt still yields under 5%, a certain 8p in every pound beats a hoped-for 8p every single time.

Auto-enrolment forces your employer to put a minimum of 3% of your qualifying earnings into your pension, on top of the 5% you pay — a combined 8% on the band of earnings between £6,240 and £50,270, as the GOV.UK workplace pensions guide sets out.

That 3% is the legal floor, not the ceiling. Many employers match additional contributions pound for pound up to a higher cap, and plenty pass back some or all of the 15% employer National Insurance they save when you sacrifice salary. Say your employer passes back the full 15%: sacrifice £200 and your employer adds £30 on top, so £230 lands in your pension for £144 of take-home pay. Every pound your employer adds is a pound you did not have to earn, tax, or invest yourself — a 100% immediate return before any fund manager gets involved.

A SIPP cannot replicate this. Open the best SIPP on the market and your employer still will not pay into it. Walk away from salary sacrifice and you are, in effect, walking away from your employer's money to chase a fee saving measured in fractions of a percent. The pension tax relief guide lays out the full arithmetic of what you forfeit.

The honest argument for a SIPP is control: you choose the funds, the platform, and the timing. The honest problem is that most people are not good at any of those three, and the evidence has been consistent for decades. Retail investors trade too much, chase last year's winners, sit in cash through drawdowns, and pay the gap between what they hold and what they would have earned by leaving it alone.

The GOV.UK page on personal pensions is refreshingly blunt that a SIPP means the money you get "depends on… how the fund's investments have performed — they can go up or down." Control cuts both ways. A workplace default fund is built for the average saver: diversified, rebalanced, and governed by a trustee who has to answer for it. A SIPP is built for the person who believes they are not average.

Most of us are average. That is not an insult — it is the single most useful fact in retirement planning. The danger of the SIPP is not that it underperforms. It is that you will intervene at exactly the wrong moment and turn a boring, adequate outcome into a permanent loss. A diversified default held for thirty years does not need you to be clever. A SIPP, by definition, does.

There is a reason auto-enrolment has lifted millions of people into pension saving who never would have opened an account on their own. The money leaves before you see it. You do not decide each month whether this is the month to pause contributions, pay for a holiday, or "wait for a better entry point." The decision has already been made for you, and retirement outcomes are overwhelmingly driven by staying invested, not by timing.

Our workplace pensions guide walks through how the 8% default actually compounds — and why the default is a floor to raise, not a ceiling to accept. The point stands: the structure does the heavy lifting that willpower never does.

Default funds also carry protection that a self-directed account does not. They are subject to a charge cap on the default arrangement, and the scheme's trustee monitors value for money year after year. A SIPP puts the entire burden of fund selection, cost control, and rebalancing on your shoulders — for decades, through recessions, job changes, and the part of your life when you are least interested in your pension. Discipline that depends on a process beats discipline that depends on your mood.

Salary sacrifice is not free of wrinkles, and the Guardian in me insists you look at them before signing anything. Because sacrifice reduces your reported salary, it can affect how much a lender will offer you for a mortgage, how maternity or paternity pay is calculated, and whether you sit above or below means-tested benefit thresholds.

But most of the side-effects cut your way. A lower reported income can restore Child Benefit that the High Income Child Benefit Charge would otherwise claw back, and it can reduce student loan repayments. The GOV.UK workplace pensions guide notes both of these explicitly — joining a workplace scheme "may mean you're entitled to an income-related benefit" and "reduce the amount of student loan repayments you need to make."

None of this is a reason to skip the pension. It is a reason to plan around the thresholds. The salary sacrifice guide covers the detail, including the edge cases where sacrificing too far becomes self-defeating. Read it once, pick a sensible number, then leave the arrangement alone.

Let me be precise about the exceptions, because pretending they do not exist is how arguments like this lose credibility.

A SIPP genuinely wins when your workplace scheme offers no salary sacrifice, when the default fund is genuinely poor, or when you are consolidating a string of old pots from past employers. It wins when you have specific, verifiable reasons — not a vague feeling that you could do better. And the SIPP guide is the right place to work out whether those reasons apply to you.

But notice what those exceptions have in common: they describe a minority of workplace schemes and a minority of savers. For everyone else, the rational move is to raise your workplace contribution, keep the salary sacrifice and the employer match, and treat the SIPP as a consolidation tool for old pots — not as the destination for this year's extra money.

The opposing case — that the fee gap makes a SIPP the right home for everything above the match — is argued in full here. Read it, then ask yourself honestly which of the two savers you are.

The comfort of the boring option is not that it is exciting. It is that it works, and it works even if you never look at it again. That is precisely what retirement savings should do.