Pension vs ISA for retirement
It's one of the most common questions in UK retirement planning: should I put my next £100 into a pension or an ISA? The honest answer is usually both — but for different reasons, at different stages of life. Here's how to think about it.
The headline difference: tax relief
When you contribute £100 to a pension as a basic-rate taxpayer, the government tops it up to £125 (and a higher-rate taxpayer can reclaim another £25 via self-assessment). The same £100 into an ISA is just £100.
That tax relief is the single biggest reason pensions usually beat ISAs on raw maths — your money starts working from a higher base.
The catch: access and tax on the way out
The trade-off is straightforward:
- Pension — Tax relief in, but locked until 55 (57 from 2028) and 75% of withdrawals are taxed as income.
- ISA — No tax relief in, but completely tax-free out, at any age, for any reason.
A worked example
£10,000 invested at age 40 for 25 years at 6% net return:
- Pension (basic rate): £12,500 gross → £53,640 at 65. Withdraw at basic rate after 25% tax-free: ~£45,594 net.
- ISA: £10,000 → £42,919 at 65, all tax-free.
Pensions usually win for the higher-rate saver who'll drop to basic rate in retirement. ISAs can win if you'd otherwise be taxed at the same rate going in and coming out.
The combo strategy: bridge with ISA, grow the pension
For early retirees, the best plan typically uses both:
- Max workplace pension match (free money), then add to a SIPP if higher-rate.
- Build a Stocks & Shares ISA pot covering 3-5 years of spending.
- At retirement, draw the ISA first (tax-free) to bridge to pension access age.
- Then drawdown from the pension, using the 25% tax-free allowance and your Personal Allowance to keep tax low.
When to favour ISA over pension
- You're planning to retire before 55 (or 57 after 2028).
- You're a basic-rate taxpayer who expects to be a basic-rate taxpayer in retirement (no rate arbitrage).
- You may need access to the money before retirement.
- You've already maxed pension allowances.
Run it through the numbers
Model your contributions in the RetireSmart calculator — try contributing the same monthly amount but stretching your retirement age from 55 to 65 and watch how much difference the extra compounding makes.
Frequently asked questions
Is a pension better than an ISA?▾
For most higher-rate taxpayers building long-term retirement wealth, a pension wins on raw maths thanks to tax relief. But ISAs offer flexibility, no access age restrictions, and tax-free withdrawals — which matters for early retirement.
How much can I put in a pension vs ISA each year?▾
ISA: £20,000/yr. Pension: up to £60,000/yr (or 100% of earnings, whichever is lower) under the annual allowance, with carry-forward of unused allowance from the previous 3 years.
Can I have both a pension and an ISA?▾
Yes — and most retirement plans benefit from using both. Pensions for tax-efficient growth, ISAs for flexible income (especially before pension access age).
Are pension withdrawals taxed?▾
25% can be taken tax-free (subject to the Lump Sum Allowance). The remaining 75% is taxed as income at your marginal rate when withdrawn.