ISA vs Pension UK
Tax-free withdrawals at any age vs. tax relief on contributions but locked until 55 (57 from 2028). Which wrapper actually leaves you with more money — and at what marginal rate.
Side-by-side comparison
| Aspect | ISA | Pension (DC / SIPP) |
|---|---|---|
| Tax relief on contributions | None | At your marginal rate (20/40/45%) |
| Annual allowance | £20,000 (across all ISA types) | £60,000 (tapered down to £10k above £260k) |
| Earliest access age | Any age (LISA: 60 / first home) | 55 (rising to 57 from 6 April 2028) |
| Tax on withdrawal | 100% tax-free | 25% tax-free + 75% taxed as income |
| Inside estate for IHT? | Yes (with APS to spouse) | Currently no (changes from April 2027) |
| Government bonus | LISA 25% on first £4,000/yr | Effective 25% on basic-rate (relief at source) |
| Investment choice | Cash, S&S, IF, LISA | Wide via SIPP; workplace usually limited fund range |
| Employer contribution | No (employer cannot contribute to your ISA) | Yes — auto-enrolment min 3% employer, 5% employee |
| Flexibility | High — withdraw + replace within tax year | Locked, then drawdown / annuity / UFPLS rules |
Worked example: £100 net into each, 30 years at 5%
Higher-rate (40%) taxpayer contributing £100 of net pay. Pension grosses up to £166 (basic-rate at source) and the higher-rate slice is reclaimed via SA. Both grow at 5% real for 30 years; withdrawn lump sum, no further contributions:
| Wrapper | Gross deposit | After 30y at 5% | Net of withdrawal tax (40%) | Net of withdrawal tax (20%) |
|---|---|---|---|---|
| ISA | £100 | £432 | £432 | £432 |
| Pension (40% relief) | £166 | £717 | ~£502 (25% lump + 75% × 60%) | ~£610 (25% lump + 75% × 80%) |
Pension wins in both retirement-rate scenarios for a current 40% saver. For a 20% saver who stays 20%, ISA and pension end up close (~£432 vs ~£458) — the LISA government bonus then tips it back to LISA-or-tied for first-home / age-60 goals.
Frequently asked questions
What's the headline difference between an ISA and a pension?
An ISA is funded with after-tax money — no relief in, but withdrawals are 100% tax-free at any age. A pension gets tax relief at marginal rate going in (basic-rate added automatically, higher/additional-rate via Self Assessment) but withdrawals are taxed as income above 25% tax-free lump sum. Pensions are locked away until age 55 (rising to 57 in 2028).
What are the contribution limits for 2025-26 and 2026-27?
ISA: £20,000 across all ISA types per tax year (Cash, Stocks & Shares, Innovative Finance, Lifetime ISA — LISA limit £4,000 inside the £20k). Pension: £60,000 annual allowance (gross including tax relief and employer contributions), tapered down to £10,000 for incomes above £260,000. The Lifetime Allowance was abolished from April 2024 and replaced with three Lump Sum Allowances.
Which gives a better outcome for a higher-rate taxpayer?
For a 40% taxpayer, a £100 net contribution becomes £166 in a pension (+ up to £41 reclaimed via SA, total relief £67). The same £100 in an ISA stays £100. If withdrawn at retirement when you become a basic-rate taxpayer, the pension wins meaningfully — even with 20% on 75% of withdrawals, the after-tax outcome beats the ISA. If still a 40% taxpayer in retirement, pension still wins narrowly thanks to the 25% tax-free lump sum.
What if I'm a basic-rate taxpayer?
A 20% taxpayer who will retire as a 20% taxpayer gets little tax-rate arbitrage from a pension — basic-rate relief in, basic-rate tax out (after the 25% tax-free lump sum). Many flexibility-focused basic-rate savers prefer ISAs for the access, especially for goals like a house deposit. The Lifetime ISA bridges the gap by adding a 25% government bonus on contributions for ages 18-39 (up to £4,000/year).
When can I access the money?
ISA: any time, no penalty. Pension: from age 55 (Normal Minimum Pension Age — rising to 57 from 6 April 2028). Earlier withdrawal triggers an unauthorised payment charge of up to 55%. LISA: from age 60 for retirement, or to buy a first home up to £450k — otherwise a 25% withdrawal charge claws back the bonus.
What about inheritance and tax on death?
Pensions are usually outside the IHT estate (subject to confirmed changes from April 2027 — see the inheritance-tax-pension change explainers). Death before 75: beneficiaries can usually take the pot tax-free. Death from 75: beneficiaries pay marginal income tax on withdrawals. ISAs form part of the estate for IHT (40% above the nil-rate band) but a spouse can inherit an Additional Permitted Subscription that preserves the tax-free wrapper.
Can I have both?
Yes — and most savers should. The optimal sequence usually starts with: (1) employer-matched workplace pension to the full match, (2) emergency cash in a Cash ISA, (3) higher-rate pension top-up if you pay 40%/45%, (4) Stocks & Shares ISA for medium-term goals, (5) LISA if eligible. Maxing both £20,000 ISA and £60,000 pension annually is achievable up to the tapered annual allowance.
What is the LISA government bonus and how does it stack against a pension?
The Lifetime ISA adds 25% to contributions up to £4,000/year (£1,000 max bonus). Mathematically, the bonus equals basic-rate pension tax relief — but withdrawals are tax-free, so for a basic-rate taxpayer the LISA matches a pension on the contribution side and beats it on the withdrawal side (no income tax on the 75% non-lump-sum portion). For higher-rate taxpayers a pension still wins.
Try the relevant calculators
- Pension Tax Relief Calculator — basic + higher-rate relief on a contribution
- Pension Annual Allowance Calculator — taper for income above £260,000
- Lifetime ISA Calculator — model the 25% bonus + 25% withdrawal charge
- Pension Drawdown Calculator — 25% tax-free lump sum + drawdown tax
- Compound Interest Calculator — model long-term growth at any rate