UK ISA Allowance 2026/27 — £20k Cap, Types, Multi-Provider Rules
Reviewed by Alex Morgan · Updated April 2026 · £20,000 cap frozen since 2017/18
The 2026/27 ISA limits at a glance
| ISA type | 2026/27 cap | Eligibility | Best for |
|---|---|---|---|
| Adult ISA (overall) | £20,000 | UK resident, 18+ for adult ISA (16+ for Cash ISA) | Combined cap across all adult ISAs |
| Cash ISA | Within £20k | 16+ resident | Short-term saving (1-3 years) |
| Stocks & Shares ISA | Within £20k | 18+ resident | Long-term investing (5+ years) |
| Innovative Finance ISA | Within £20k | 18+ resident | Higher-risk peer-to-peer lending |
| Lifetime ISA | £4,000 within £20k | 18-39 to open, contribute to 50 | First home (≤£450k) or retirement at 60 |
| Junior ISA (Cash + S&S) | £9,000 (separate) | Under-18s | Long-term saving for child; locks until 18 |
The April 2024 multi-ISA reform — still relevant in 2026/27
Until April 2024, you could only contribute to one ISA of each type in a tax year. Open a second Cash ISA and you'd lose the tax wrapper on the second one. From 6 April 2024, the rule loosened: multiple ISAs of the same type are now allowed in a single year, as long as the £20,000 total isn't breached.
Practical impact: you can now chase the best Cash ISA rate by splitting across two or three providers, or run separate Stocks & Shares ISAs at different platforms (e.g. a fee-efficient SIPP-platform S&S ISA for cheap funds, plus a higher-fee robo-advisor S&S ISA for managed allocation). The change reflects a market reality where customers were already moving providers and the old "one of each per year" rule was just an administrative trap.
Still capped at one each: Lifetime ISA (one LISA per tax year, full stop) and Junior ISAs (one Cash JISA and one S&S JISA per child). The Innovative Finance ISA technically allows multiples but the IF-ISA market has shrunk significantly since the 2018-2020 P2P contraction — most savers will not encounter it.
The £20,000 cap — frozen since 2017/18
The ISA allowance has been £20,000 for nine consecutive tax years. Inflation since April 2017 means the real-terms allowance has fallen significantly:
| Tax year | Cash allowance | Real-terms (CPI to April 2026) |
|---|---|---|
| 2017/18 | £20,000 | ~£26,500 |
| 2020/21 | £20,000 | ~£24,500 |
| 2023/24 | £20,000 | ~£21,800 |
| 2026/27 | £20,000 | £20,000 (base) |
The freeze is a fiscal-drag stealth tax — high-saving households increasingly hit the cap and have to hold investments outside the ISA wrapper, where dividend tax and CGT bite (especially with the £500 dividend allowance and £3,000 CGT allowance both at multi-decade lows).
Cash vs S&S vs Lifetime — which one?
- Cash ISA — best for: emergency fund, house deposit within 3 years, retirees needing capital preservation. Top 2026 providers offer 4-5% on easy-access; 5-6% on 1-year fixed. FSCS-protected to £85k per provider.
- Stocks & Shares ISA — best for: long-term wealth building, retirement supplement, anyone with a 5+ year horizon. Historic UK equity returns ~7% nominal vs ~4% best Cash ISA. Capital at risk. Watch fees: cheap platforms are 0.15-0.25% + fund fees.
- Innovative Finance ISA — niche; only for sophisticated investors comfortable with peer-to-peer lending risk and reduced FSCS protection.
- Lifetime ISA — best for: first-time buyers under 40 saving for a home up to £450k, OR retirement supplement for those who've maxed pension allowance. 25% government bonus is the headline draw; the £450k cap and 25% withdrawal penalty for non-qualifying use are the catches. Full LISA guide.
- Junior ISA — best for: long-term saving for a child. Cannot be accessed until age 18. £9,000/year × 18 years compounded easily reaches £200k+ for a baby starting at birth.
ISA transfers — the right way
Always transfer ISAs through the new provider — never withdraw money and re-deposit it. A withdrawal breaks the tax wrapper for that money permanently; redepositing uses fresh ISA allowance. The transfer route preserves the wrapper.
- Cash ISA transfer: must complete within 15 working days from when the new provider receives the transfer instruction.
- Stocks & Shares ISA transfer: must complete within 30 calendar days.
- Current-year contributions: must transfer in full (you cannot split this year's £20k after partial transfer).
- Prior-year contributions: can be partially transferred — split your £200k accumulated ISA across multiple platforms freely.
- Cross-type transfers: Cash ISA → S&S ISA allowed; LISA → LISA only; Junior ISA → Junior ISA (or roll over to adult ISA at 18).
Flexible ISAs — withdraw and replace
A "flexible" ISA lets you withdraw money and replace it within the same tax year without using up additional allowance. Example: contribute £20,000 in May, withdraw £8,000 in October for an emergency, replace the £8,000 by 5 April → you still have a fully-funded £20,000 ISA. Non-flexible ISAs treat the withdrawal as permanent — replacement comes from new allowance.
Flexibility is provider-specific: most Cash ISAs are flexible; most Stocks & Shares ISAs are not (replacement of cash withdrawals is allowed at some platforms but selling shares to withdraw and re-buying is generally not within the flexibility rule). Lifetime ISAs and Junior ISAs cannot be flexible. Always check the provider's documentation before relying on flex behaviour.
The British ISA that wasn't
Jeremy Hunt announced a "British ISA" in the March 2024 Spring Budget — a £5,000 additional allowance for UK-listed shares only, on top of the standard £20,000. Provider implementation was delayed pending detailed consultation. Rachel Reeves scrapped the proposal in October 2024 before any provider had launched the product. So in 2026/27 the ISA framework is unchanged from April 2024 — £20,000 main, £4,000 LISA, £9,000 Junior. No British ISA exists or is currently planned.
Pair this with
- → UK Lifetime ISA 2026 — the £4k slice with 25% bonus
- → UK Dividend Tax 2026/27 — what ISAs shelter you from
- → UK Capital Gains Tax 2026/27 — companion shelter strategy
- → UK Pension Annual Allowance 2026/27 — the bigger-allowance cousin
- → UK Self Assessment 2026/27
- → UK Marriage Allowance 2026