Best cash ISA rates in the UK — 2026 guide

The cash ISA is the simplest piece of furniture in the British personal-finance house. You put money in. It earns interest. HMRC doesn't take a slice of that interest, no matter how much you eventually hold.

That bit hasn't changed for years. What changes — every few months, sometimes every few weeks — is who's actually paying the best rate. This guide is about the second bit.

How the £20,000 allowance works

Each tax year (6 April to the following 5 April), you can put up to £20,000 into ISA wrappers in total. That's across cash ISAs, stocks & shares ISAs, lifetime ISAs (capped at £4,000 inside this £20,000) and innovative finance ISAs combined. You can spread it however you like.

A few things that catch people out:

• The allowance doesn't roll over. Anything you don't use by 5 April is gone. There's no carry-forward.
• Withdrawals don't free up the allowance. Unless your provider offers a flexible ISA, taking money out doesn't let you put it back in the same year without it counting again. Most providers now do offer flexibility, but check yours.
• Transfers don't count. Moving an old ISA from one provider to another doesn't use any of this year's allowance — provided you use the official transfer process, not a withdraw-and-redeposit.

What "best rate" means in practice

There's no single "best" cash ISA rate, because the right product depends on how long you can lock the money away.

Type	Typical 2026 rate range	Lock-in	Who it suits
Easy-access cash ISA	4.20% – 4.80% AER	None	Money you might need within 12 months
1-year fixed cash ISA	4.50% – 5.10% AER	12 months	Money you definitely won't need until next year
2-year fixed cash ISA	4.40% – 5.00% AER	24 months	Money you're saving toward a 2027 goal
Regular cash ISA	5.50% – 6.50% AER	None usually, but capped monthly deposit	Money you're drip-feeding from monthly salary

Two things to note. First, regular savers often pay the headline-grabbing rate but cap the monthly deposit at £200–£500, so the cash sitting outside the regular saver still needs a home. Second, fixed-rate ISAs are often "fixed and final" — once you've opened it, additional deposits aren't allowed.

Where to actually look up today's rates

Rates move too fast for this page to ever be the live source of truth. The places I check first:

• Moneyfacts — the most thorough by far. Filter by ISA type and minimum deposit.
• MoneySavingExpert's "Top ISAs" page — fewer products, but updated quickly when something market-leading lands.
• The Times' weekly Money pages (Saturday) — the print version still gets early notice of withdrawals.

Whichever source you use, sort by "AER" not "gross rate", and ignore introductory bonus rates that drop after the first 12 months. The number that matters is the rate you'll be earning in month 13.

When a stocks & shares ISA wins instead

The cash ISA is wonderful and dull. A stocks & shares ISA is volatile but has the only realistic chance of beating long-term inflation.

The rough rule of thumb most planners use: any money you might want to spend in the next three to five years belongs in cash. Anything you genuinely won't touch for longer than five years should be at least partly in a stocks & shares ISA, almost regardless of your appetite for risk. The maths is straightforward — inflation at 3% halves the purchasing power of cash in about 24 years, and that's a real number, not a doomsday scenario.

If you split the £20,000: a common pattern is £5,000–£10,000 to a cash ISA for the rainy-day fund, and the rest into a low-cost global index inside a stocks & shares ISA.

The provider questions that matter

When you're picking a specific cash ISA, three details tend to make the difference:

1. Does it accept transfers in? If you have ISAs from previous tax years sitting at low rates, the only way to consolidate them at the new provider is via transfer. Many top-rate accounts quietly don't accept transfers.
2. Is it flexible? A flexible ISA lets you withdraw and redeposit within the same tax year without using more of the allowance. Worth its weight in gold if you might dip in.
3. What's the FSCS coverage? Standard £85,000 per banking group. If you have more than that, split across providers — and check that two separate brand names aren't actually under the same banking licence (Halifax and Bank of Scotland share theirs, for example).

The half-truth about "tax-free"

Cash ISAs are advertised as tax-free, and they are — interest never appears on your self-assessment. But you might not actually need a cash ISA to pay no tax on cash interest, depending on your income.

Most basic-rate taxpayers get a Personal Savings Allowance of £1,000 of interest tax-free outside any ISA wrapper. Higher-rate taxpayers get £500. Additional-rate taxpayers get nothing.

So: if you're a basic-rate taxpayer earning 4.5% on a non-ISA savings account, you'd need a balance of more than about £22,000 before any interest becomes taxable. Below that, an ISA gains you nothing on tax. Above it, the ISA matters more every year.

What I do personally

Three small confessions to close out:

• I keep about three months' expenses in an easy-access cash ISA. The exact provider changes every couple of years; I check the table and switch when the gap to market-leader gets uncomfortable.
• The rest of my ISA allowance goes into a low-cost global index fund inside a stocks & shares ISA. I haven't held a regular saver in five years — the cap-on-deposit makes them more useful for newly-saving twenty-somethings than for people with an existing pot.
• I never lock money away in a multi-year fixed-rate ISA. I'd rather lose 0.2 percentage points of interest and have the flexibility to move it.

That's the calculus, not advice. Your numbers will be different — which is the whole point of doing the maths.

---

Last updated 17 May 2026. Rates change frequently — verify any figure against the provider's own website before you act. RichQuid earns commission from some ISA providers we link to, but not from anyone mentioned by name in this article. See our disclaimer.