Salary Sacrifice Into Your Pension Before You Overpay a 5% Mortgage — Higher-Rate Taxpayers Are Giving Up 42p in the Pound for Nothing

For a higher-rate taxpayer in England, Wales or Northern Ireland, the marginal income tax rate above £50,270 is 40%. Add 2% employee National Insurance on the same band, and every pound of gross salary becomes 58p in your bank account.

That is the wedge. £1,000 of mortgage overpayment costs you £1,724 of gross salary to produce. £1,000 of pension contribution, via salary sacrifice, costs you £1,000 of gross salary — and the take-home you give up is £580, because HMRC and HMRC alone hands back the 42p you were about to pay them.

HMRC's rules on pension tax relief are unambiguous: a higher-rate taxpayer can reclaim 20% on top of the 20% automatically applied at source. Salary sacrifice collapses both into a single payroll instruction and adds back the 2% NIC saving on top.

For those caught in the £100,000–£125,140 personal allowance taper, the marginal rate is 62% (40% income tax + 2% NIC + 20% lost personal allowance). Every £1,000 of mortgage overpayment in that band costs £2,632 of gross salary. The same gross salary sacrificed produces £2,632 in pension — a 2.6x uplift before growth.

No mortgage in the UK pays a 60% tax-relief bonus on overpayments. None ever will.

Take a 40-year-old higher-rate taxpayer with a 25-year mortgage at 5.00% fixed for 5 years (the average 5-year fix at 75% LTV today, per the Bank of England's published quoted rates). They have £580 a month of spare take-home to deploy.

Option A: pay £580 a month off the mortgage. Over 25 years, at 5% compounding, that £580 of saved interest grows in the implicit return sense to £580 × 1.05^25 = £1,963 per pound deployed. For £174,000 deployed over 25 years, the implicit lifetime benefit is roughly £400,000 in avoided interest plus principal repayment — meaningful, but bounded by the mortgage's own rate.

Option B: tell payroll to sacrifice £1,000 of gross salary a month into the pension. The take-home cost is the same £580 (because £1,000 gross was £580 net). £1,000 a month for 25 years at 6% real annualised growth (the long-run real return on a global tracker fund) compounds to roughly £693,000.

At 57, draw 25% as a tax-free lump sum — £173,000 under the current lump sum allowance of £268,275. The remaining £520,000 drawn down at the 20% basic-rate retiree band yields £416,000 net. Total net to you: £589,000 — from the same £580 a month of forgone take-home.

Add a 15% employer National Insurance pass-through — increasingly common since employer NIC rose to 15% in April 2025 — and the pension contribution becomes £1,150 a month, yielding £797,000 gross and £677,000 net after the same drawdown.

A guaranteed 5% post-tax return sounds good. It is good — for a basic-rate taxpayer with no pension allowance left. For a higher-rate taxpayer, it is the wrong yardstick.

The correct comparison is: what return does a £1 of gross salary earn if I overpay the mortgage vs if I sacrifice it into a pension?

• Mortgage: £1 of gross becomes £0.58 of net. £0.58 of net overpayment earns 5% post-tax on £0.58. After 25 years: £0.58 × 1.05^25 = £1.96.
• Pension: £1 of gross stays as £1 in the wrapper. £1 grows at 6% real for 25 years = £4.29. Draw 25% tax-free + 75% at 20% basic-rate retiree band = £3.65 net. £3.65.

The pension route returns £3.65 per £1 of gross salary. The mortgage returns £1.96. That is an 86% premium, before employer NIC pass-through, before any retirement income shaping, before any tax-free lump sum used for the mortgage payoff itself.

The Bank of England's published quoted rates show 2-year fixed mortgages at 5.14% and 5-year fixed at 5.00% as of the latest April 2026 data. Trackers and SVRs are higher at 6.60%. Even the SVR's 6.60% guaranteed return is dwarfed by a 6% real pension return with a 42% upfront tax kicker.

The Guardian counter-argument runs: a pension is locked until 57 — rising to 58 from April 2028. You cannot eat it. The mortgage is in front of you, week by week.

This is true, and it is also exactly why the pension is the better mortgage payoff vehicle.

At 57, you can take 25% of the pension as a tax-free lump sum, up to the £268,275 lump sum allowance. On a £693,000 pot, that is £173,000 in your hand, tax-free, in one cheque.

A 25-year mortgage of £250,000 taken at 40 has roughly £140,000 outstanding at 57. The tax-free lump sum clears it outright, with £33,000 spare. The remaining £520,000 of pension funds your retirement.

Meanwhile the mortgage-overpayer arrives at 57 with: a paid-off house worth (say) £600,000, no liquid assets to speak of, and a pension that holds only the workplace minimum because 25 years of spare take-home went to the bank instead.

Which net worth do you prefer at 57: house £600k + pension £693k = £1.29m, or house £600k + pension £100k = £700k? The answer is the same in every scenario the maths permits.

The pension AVC dominates the mortgage overpayment for higher-rate taxpayers in almost every scenario. There are three cases where the answer is genuinely different:

1. You are a basic-rate taxpayer. The relief is 20%, not 40%. £1 of gross becomes £0.80 of net. The mortgage at 5% returns £0.80 × 1.05^25 = £2.71 per £1 of gross. The pension at 6% real returns £4.29 gross, £3.43 net after 20% drawdown tax (assuming no headroom for tax-free withdrawal). Pension still wins, but the margin is 27%, not 86%. For basic-rate taxpayers the calculation gets close enough that liquidity and certainty preferences can tip it.

2. You are within 5 years of retirement and the mortgage has 25 years to run. Sequence-of-returns risk on the pension matters more than the tax wedge if you are drawing at 60 and the market drops 30% in your first year. A mortgage cleared at 55 is cleared. A pension that has just lost 30% on the cusp of drawdown is a different conversation.

3. Your pension is fully invested in expensive active funds. A 1.5% ongoing charges figure on a tracker eats one quarter of a 6% real return. The mortgage rate is what it is; the pension return is what the fund delivers. The FCA's value-for-money requirements on workplace schemes help, but if you cannot move to a low-cost SIPP, the spread narrows.

None of these cases describes the typical 40-year-old higher-rate-tax-paying mortgage holder with 25 years to run. For them, the pension wins. Stop overpaying the mortgage and instruct your payroll department this month.

Three routes into the pension. They differ in mechanism but converge on the same destination — pre-tax money inside the wrapper.

Salary sacrifice is the most efficient. You agree with your employer to reduce gross salary by, say, £1,000 a month. The £1,000 goes into the pension. You save income tax (40% on it) and employee NIC (2%) — that is the 42% headline relief. Your employer saves their own NIC contribution (15% since April 2025), and many employers pass some or all of that through into your pension. Outcome: £1,150 in the pension for £580 of forgone take-home.

Workplace AVC (additional voluntary contributions) sits inside your existing workplace pension scheme. Most schemes allow you to dial up your contribution rate above the minimum. The contributions go in gross via net-pay arrangement, or via relief at source with the basic 20% added back and the additional 20% reclaimed on Self Assessment. Less elegant than salary sacrifice — no NIC saving for you, none for the employer — but still the same income tax relief.

Relief at source into a SIPP. Open an account with an investment platform, pay in net. The platform claims 20% from HMRC for you. You claim a further 20% via Self Assessment. Same outcome on income tax, no NIC saving on either side. Useful if you have already maxed your workplace AVC route or want to invest in cheaper funds.

The order of preference for higher-rate taxpayers: salary sacrifice → workplace AVC → SIPP. The choice between them is administrative. The choice to use one rather than overpay the mortgage is financial.

For more on how the wrappers compare, see our ISA vs pension guide, and use our mortgage repayment calculator to see the bounded benefit of the overpayment route before you commit.

There is one Guardian point that holds: pension rules are political. The lump sum allowance was £268,275 yesterday and could be £200,000 next year. The pension access age was 55 a decade ago, 57 from April 2028, and rising. The 25% tax-free portion has been on the rumour list at every Budget since 2010.

This is not a reason to overpay the mortgage. It is a reason to diversify the tax wrappers you save through — ISA alongside pension, gilts and S&S in different sleeves. The Guardian's case for overpaying the mortgage is really a case against putting 100% of long-term savings in any one wrapper. That is correct, and it is solved by splitting AVCs with ISA contributions, not by sending all of it to the bank.

The counter-argument in this debate is worth reading on the liquidity and political-risk points. But on the maths — the actual numerical comparison of £1 of gross salary into one wrapper versus the other — the pension AVC wins by a margin that no plausible political rule change closes.

This article is for informational purposes only and does not constitute financial advice. Pension rules, tax bands and mortgage rates change. Your personal circumstances — marginal rate, employer pension scheme, mortgage type, retirement plans, attitude to risk — determine the right answer for you, not generic comparisons. The worked examples assume long-run real returns that are not guaranteed; pensions can fall as well as rise. You should seek independent financial advice before making any pension contribution, salary sacrifice arrangement or mortgage overpayment decision.