UK ISA Allowance 2026: Cash, Stocks, LISA and the Best Use of £20,000

The four ISA types

Cash ISAs hold cash and pay tax-free interest. Stocks and Shares ISAs hold shares, funds, ETFs and investment trusts, with all dividends and capital gains tax-free. Lifetime ISAs (LISAs) are designed for first home purchase or retirement and add a 25% government bonus. Innovation Finance ISAs hold peer-to-peer loans (a small and shrinking category in 2026).

All four share the £20,000 annual allowance. From April 2024 you can pay into multiple ISAs of the same type in the same tax year — for example a Cash ISA with one bank and another Cash ISA with a different bank, provided total contributions do not exceed £20,000.

Cash ISA vs Personal Savings Allowance

Basic-rate taxpayers receive a Personal Savings Allowance (PSA) of £1,000 of tax-free interest outside an ISA; higher-rate taxpayers £500; additional-rate taxpayers nothing. With savings rates at 4 to 5 percent in 2026, a basic-rate taxpayer with £25,000 in savings is already at the PSA limit, and any further savings outside an ISA are taxed.

The case for a Cash ISA strengthens with every percentage point of interest and every pound above the PSA. For higher-rate taxpayers, even £15,000 of cash savings outside an ISA is producing taxable interest. For additional-rate taxpayers, every penny of interest is taxable.

Stocks and Shares ISA — the long-term winner

Over the long term, equities have produced real returns of 4 to 6 percent above inflation, dwarfing cash. £20,000 a year invested in a global index fund inside an ISA, growing at 6 percent real, becomes around £370,000 over 15 years and £870,000 over 25 years — entirely tax-free.

Charges matter enormously over decades. A platform charging 0.45% plus a fund charging 0.22% (typical for a passive global index) costs about £1,300 a year on a £200,000 pot. The same pot in higher-fee actively managed funds at 1.5% all-in costs £3,000 a year — £100,000+ less wealth over 25 years for no proven extra return.

Lifetime ISA — the 25% bonus

Anyone aged 18 to 39 can open a Lifetime ISA. You can contribute up to £4,000 per year (counts toward the £20,000 ISA allowance), and the government adds a 25% bonus — up to £1,000 per year free. The bonus continues until age 50.

LISA funds can be used penalty-free for a first home purchase up to £450,000 anywhere in the UK, or after age 60 for retirement. Withdrawals for any other reason incur a 25% government penalty — which is more than just losing the bonus, because it's 25% of the withdrawal amount, not the original contribution. Use the LISA only if you're confident you'll use it for one of the two intended purposes.

Best ISA mix by life stage

First-time buyer aged 18 to 39 saving for a deposit within the next 5 years: max LISA (£4,000) for the bonus, balance in Cash ISA. Mid-30s with mortgage and emergency fund: max Stocks and Shares ISA in a low-cost global tracker. 50s with high cash needs and large savings: split between Cash ISA (3 to 6 months expenses) and Stocks and Shares ISA (longer-term growth).

Retirees drawing income: keep 1 to 2 years of spending in a Cash ISA for stability, balance in a Stocks and Shares ISA producing tax-free dividends. Tax-free withdrawals from an ISA do not count toward the personal allowance, so they don't push pension income into a higher tax band.

Frequently asked questions