Compare UK ISA types - 2026/27

The annual allowance is the most-cited number, but it conceals a structural quirk: Cash, Stocks & Shares, Lifetime, and Innovative-Finance ISAs all share a single combined £20,000 pot. Subscribe £5,000 to a Cash ISA and you have £15,000 left across the other three types. The Lifetime ISA further restricts itself to a maximum of £4,000 inside that £20K pot, with the rest available to the other three. The Junior ISA is the exception - it has a separate £9,000 per-child allowance that does not eat into your adult pot.

Risk and return run in tandem and are not really comparable across rows. The Cash ISA's 4.5% headline is guaranteed contractually for the term, FSCS-protected to £85,000, and inflation-vulnerable over long horizons. The Stocks & Shares ISA's 5% real (FTSE All-Share TR 30-year) is the long-run mean of an instrument that can lose 30% in a calendar year and recover within 18-36 months. The Innovative-Finance ISA's 7% is a headline P2P-platform yield before default losses; FSCS does not protect P2P lending capital, so the figure is closer to a target than a typical outcome.

The Lifetime ISA's 25% bonus is the highest "risk-free return" in UK personal finance, provided you can live with the withdrawal restriction (first home under £450,000, age 60+, or terminal illness). The lock-in interacts strangely with the bonus: a non-qualifying withdrawal incurs a 25% charge on the topped-up balance, which is more than the original 25% bonus added to your contribution, netting you less than you put in. Read the Lifetime ISA page before opening one.