Your £20,000 Cash ISA Allowance Gets Cut to £12,000 Next Year — Use It or Lose It

The ISA rules currently allow you to put up to £20,000 per tax year into any combination of ISA types — cash, stocks and shares, innovative finance, or Lifetime ISA. From 6 April 2027, savers under 65 will be capped at £12,000 in cash ISAs specifically.

The remaining £8,000 of your allowance can still go into stocks and shares ISAs or other ISA types. The overall £20,000 ceiling doesn't change. But if you're someone who uses your entire ISA allowance in cash — and millions of people do — you'll lose £8,000 of tax-free cash savings capacity every single year.

Savers aged 65 and over keep the full £20,000 cash ISA allowance. The government's logic: older savers are more likely to need accessible, low-risk cash. Younger savers should be taking more investment risk.

For a full breakdown of all ISA types and how they work, see our ISA hub. If you're specifically considering a Lifetime ISA before the scheme closes, our LISA guide covers the withdrawal trap most people miss.

£8,000 per year of lost cash ISA space compounds badly over time. With the Bank of England base rate at 3.75% and the best easy-access cash ISAs paying north of 4%, that's real money going unshielded from tax.

A basic-rate taxpayer has a £1,000 Personal Savings Allowance, so modest cash savings outside an ISA attract no tax anyway. But higher-rate taxpayers get only £500, and additional-rate taxpayers get nothing. For them, the cash ISA is the primary shelter.

Run the numbers over a decade. A higher-rate taxpayer who currently puts £20,000 into a cash ISA annually at 4% would accumulate roughly £240,000 in tax-free cash after 10 years. Under the new rules, they'd cap at £12,000 per year in the cash ISA and need to put the other £8,000 somewhere else — either in a taxable savings account (where 40% of the interest goes to HMRC) or in a stocks and shares ISA.

Over 10 years at 4%, that £8,000 annual difference in tax-free cash produces roughly £96,000 less in the cash ISA. The tax cost? About £1,500–£2,000 per year for a higher-rate taxpayer if that money sits in taxable savings instead. That's £15,000–£20,000 in avoidable tax over a decade.

The Personal Savings Allowance is often cited as a reason cash ISAs don't matter. That argument falls apart for anyone with serious savings. A higher-rate taxpayer with £50,000 in non-ISA savings at 4% earns £2,000 interest — but only £500 is tax-free. The remaining £1,500 is taxed at 40%, costing £600 per year. Inside an ISA, that £600 stays in your pocket.

For a detailed comparison of where to put your savings, see our savings hub — and if you're weighing cash against Premium Bonds, our Premium Bonds analysis has the maths.

Rachel Reeves didn't cut the cash ISA limit because she's worried about your savings habits. The Treasury wants capital flowing into UK equities. The Treasury Committee's report on cash ISAs made the case plainly: too much ISA money sits in cash earning returns that barely beat inflation, when it could be funding British businesses through the stock market.

There's a tension here worth naming. The government is effectively telling under-65s that cash savings above £12,000 per year don't deserve tax protection — while simultaneously benefiting from a high base rate that makes cash genuinely attractive. At 3.75% base rate, with easy-access accounts paying 4%+, the argument for cash over volatile equities is stronger than it's been in 15 years.

The cynical read: this is a stealth tax on cautious savers. The charitable read: it's a nudge toward better long-term returns. The truth is probably both.

You have 18 days left in the 2025/26 tax year. Here's the priority list:

Max out your cash ISA now. If you have spare cash and haven't used your £20,000 ISA allowance, this is the last tax year where you can put the full amount into cash. Every pound you shelter now stays tax-free permanently — existing ISA balances are not affected by the new rules.

Consider fixed-rate cash ISAs. The best 1-year fixed cash ISAs are paying above 4%. Locking in now means you earn a competitive rate while the allowance is still at its maximum. Even if rates fall later, your capital and interest remain tax-free inside the wrapper.

Don't ignore stocks and shares ISAs. The new rules assume you'll redirect the £8,000 into investments. If you've never used a stocks and shares ISA, 2025/26 is the year to start. A low-cost global index tracker inside an ISA costs as little as 0.12% annually and gives you exposure to thousands of companies. The ISA overview on gov.uk confirms you can split your £20,000 across multiple ISA types.

Couples should coordinate. Two people means £40,000 of cash ISA space in 2025/26. If one partner has spare cash and the other hasn't used their allowance, a gift between spouses is tax-free and lets both allowances be maximised.

If you're under 65 and currently saving more than £12,000 per year in cash ISAs, the question from April 2027 isn't whether to invest — it's what to invest in.

The simplest option: a global index tracker in a stocks and shares ISA. A fund tracking the FTSE All-World or MSCI World Index gives you exposure to thousands of companies across dozens of countries. Annual fees start at 0.12% with providers like Vanguard. Over any 20-year period in history, global equities have outperformed cash — though past performance guarantees nothing about the future.

The emotional barrier is real. Cash feels safe. You see the interest accumulate monthly. Stocks fluctuate daily and can fall 30% in a bad year. But the government is betting that for under-65s with decades until retirement, the long-term equity premium justifies the short-term volatility.

If you're not ready for full equity exposure, consider a middle ground: a 60/40 fund that blends equities with bonds. You'll get less growth than pure equities but more stability than a 100% stock portfolio. Vanguard's LifeStrategy range and iShares' World Balanced ETF both offer this in a single fund.

For platform comparisons and fee breakdowns, see our investing hub and our flat-fee vs percentage-fee ISA analysis. Use our ISA calculator to model how different allocation splits affect your long-term returns.

Keeping the full £20,000 cash ISA allowance for over-65s sounds generous. But it creates an odd incentive structure. A 64-year-old can shelter £20,000 in cash; a 65-year-old gets the same privilege. A 63-year-old gets £12,000. The age threshold creates a cliff edge that will catch people out.

More practically, this means retirees drawing down pensions can continue to shelter cash withdrawals in ISAs at the full rate — useful for managing income in retirement. But younger savers building emergency funds, saving for a house deposit, or just wanting the certainty of cash? They're penalised relative to the generation that already had decades of tax-free saving.

The policy will be reviewed. Whether the £12,000 limit stays, shrinks further, or gets index-linked to inflation is anyone's guess. What's certain: the direction of travel is toward smaller cash ISA allowances and larger incentives for equity investment.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice before making any investment decisions.