Use Your Full £20,000 Cash ISA Allowance Now — It Drops to £12,000 in 2027

The 2026/27 tax year is the last chance for under-65s to use a full £20,000 Cash ISA allowance before the limit is cut to £12,000 from 6 April 2027, under the ISA reform anti-circumvention rules factsheet published by GOV.UK. The overall £20,000 ISA allowance across all ISA types stays the same — but the portion you're allowed to hold specifically in cash is shrinking.

What's changing and why

From 6 April 2027, under-65s will only be able to put £12,000 of their annual ISA allowance into cash, with the remaining £8,000 needing to go into a Stocks and Shares or Innovative Finance ISA to use the full £20,000 total, according to IG's explainer. Savers aged 65 and over are exempt from the cash cut and retain the full £20,000 cash allowance, with eligibility starting from the tax year in which you turn 65, per Starling Bank.

The stated policy goal is to nudge long-term savers toward investing rather than cash, on the view that too much household wealth sits in low-growth cash savings. Whether that's the right call for your own situation depends on your time horizon and risk tolerance — but the practical deadline is clear either way.

Checklist: making the most of this tax year

• Check how much of your £20,000 allowance you've used so far this tax year (6 April 2026 to 5 April 2027) via your ISA provider's app or statement.
• If you're under 65 and want to hold cash long-term, consider using more of this year's allowance for cash now, since next year's cash-specific cap drops to £12,000.
• Compare Cash ISA rates — several providers are currently offering competitive fixed and easy-access Cash ISA rates as the deadline approaches; check Which?'s savings tables or a dedicated savings comparison site.
• Don't forget the Lifetime ISA if you're saving for a first home or retirement and are aged 18-39 — it sits outside the general Cash/Stocks split debate and carries its own 25% government bonus.
• Review your risk appetite before shifting money into a Stocks and Shares ISA purely to "use up" the allowance — investment ISAs carry market risk that cash ISAs don't.
• Use the transfer rules, not withdrawal, if moving between ISA types — withdrawing and redepositing can lose your tax-free wrapper status for that money; always request an official ISA transfer.

International comparison

The UK's £20,000 annual ISA allowance remains generous by international standards. The nearest US equivalent, the Roth IRA, caps annual contributions at roughly $7,000 and phases out for higher earners — though it has no age-based deadline like the ISA and no limit on the number of years you can contribute across a lifetime. Australia's equivalent tax-advantaged vehicles are largely pension-based (superannuation) rather than a flexible, instantly-accessible wrapper like the ISA.

Key Numbers

• Total ISA allowance 2026/27: £20,000
• New Cash ISA cap from April 2027 (under-65s): £12,000
• Over-65s retain full cash allowance: £20,000
• US Roth IRA annual limit: roughly $7,000

Sources

• GOV.UK: ISA reform 2027 anti-circumvention rules factsheet
• IG: Cash ISA changes 2027
• Starling Bank: ISA allowance 2026/27
• Hargreaves Lansdown: ISA allowance 2026/2027
• IRS: retirement topics — IRA contribution limits

Educational content only — not financial advice.