Cash ISA Rates Ranked: The Best Accounts for the 2026/27 Tax Year and What They Actually Pay After the Bonus Expires

Every comparison site ranks easy access cash ISAs by headline AER. That ranking flatters the providers and misleads the saver. Here is the same table rebuilt with the rate you actually keep after the introductory bonus expires.

The chart is the story. Trading 212 sits at the top of every league table with 4.62%, but the 1.02% bonus runs for only 12 months. The underlying variable rate is 3.60% — 15 basis points below the 3.75% BoE base rate. Plum's 4.61% is worse: the 2.07% bonus props up a 2.54% base, which means you lose 45% of your interest the day the promotion ends.

Moneybox deserves a warning label. Its headline 4.06% is a 3.16% bonus on a 0.90% underlying rate — one of the most aggressive teasers in the market — and the deal is gated by a hard three-penalty-free-withdrawals cap. Breach it and the rate drops to 0.75%. That is not easy access. That is conditional access with a PR-friendly number.

Cynergy Bank at 4.17% is the honest option. No bonus. No withdrawal cap. Unlimited transfers in. The rate you see on day one is the rate you still earn in year three, assuming the BoE doesn't move. For anyone who won't actually switch providers every 12 months — which is most people — this is the rational choice, and FSCS protection runs to the full £120,000 per person per banking licence.

Virgin Money's 4.15% is the best name-recognition pick and shares its FSCS umbrella with Nationwide. If you already bank with Nationwide, stay at Virgin — you cannot stack two FSCS limits across the same licence.

Six weeks ago, fixing looked obvious. Markets priced two more BoE cuts by year-end, and easy access rates looked destined to follow. The Iran conflict changed the calculus. Oil spiked, sterling wobbled, and the 10-year gilt yield jumped from 4.43% in February to 4.70% in March — a 27 basis point move in six weeks, the sharpest since the 2022 mini-budget. Fixed-rate ISA pricing tracks gilt yields more closely than base rate, so fixes repriced upward even as the BoE held steady.

The practical consequence: the best fixed rates now sit above the best no-bonus easy access rate. A Chetwood Bank 3-year or 5-year fix pays 4.55%. An Investec one-year fix pays 4.52%. The overall top pick — an 18-month fix — pays 4.56%. All of those beat Cynergy's 4.17% easy access by 35 to 39 basis points.

For high-street comfort: NatWest's one-year fixed cash ISA pays 4.20% on balances above £25,000, Santander offers 4.50% across one, two, three, and five-year terms, and Leeds Building Society sits at 4.50% for one year. None of these require the gymnastics that turbo-charged bonus accounts demand.

When does fixing make sense right now? Three tests: you are confident the BoE will resume cutting once the Middle East energy shock passes (the February MPR still projects easing over 2027-28); you are a higher-rate taxpayer whose PSA is already breached; and you don't need the cash for the term. Tick all three and a two-year fix at 4.50% is the dominant strategy — you lock in a real yield premium that easy access rates will almost certainly not match by summer 2027.

Don't fix if you might need the money. Cash ISA providers must legally allow access, but early withdrawal penalties routinely cost 60 to 365 days of interest — enough to wipe out the premium the fix was supposed to earn you.

The Personal Savings Allowance gives basic-rate taxpayers £1,000 of tax-free interest, higher-rate taxpayers £500, and additional-rate taxpayers nothing at all. At 2026 rates, that allowance gets eaten faster than most people realise.

At Cynergy's 4.17%, a basic-rate taxpayer breaches the £1,000 PSA at just £23,981 of savings. A higher-rate taxpayer breaches the £500 PSA at £11,990. Additional-rate taxpayers start paying tax on the first penny of interest in a taxable account.

Here is the comparison that matters. Take a higher-rate taxpayer with £20,000 in a 4.30% standard savings account (the kind of rate Chase or Chip offer). The gross interest is £860. After the £500 PSA and 40% tax on the remaining £360, the net is £716. The same £20,000 in Cynergy's 4.17% cash ISA earns £834 — all tax-free. The ISA wins by £118 per year, every year, on a single £20,000 lump.

For additional-rate taxpayers the gap is wider still. And because ISA interest compounds tax-free in perpetuity, the savings stack. A couple who have maxed their allowance every year since 1999 now hold well over £480,000 in combined ISA wrappers — interest on which is permanently shielded, regardless of future tax rule changes.

If you are weighing the broader choice, our ISA hub breaks down all four ISA types and how they interact. For the direct cash-vs-taxable-savings question with worked examples, see our detailed PSA comparison.

The 2026/27 ISA allowance opened on 6 April. You have 350 days to use it. Any unused portion disappears forever at midnight on 5 April 2027.

This matters more than in an average year. From 6 April 2027, the cash ISA allowance for under-65s drops from £20,000 to £12,000, while the overall ISA allowance stays at £20,000 — meaning the extra £8,000 must go into stocks and shares, innovative finance, or Lifetime ISAs — our Charles Stanley Direct review covers one flexible S&S ISA option for that spillover. Over-65s keep the full £20,000 cash allowance. 2025/26 was the last year at £20,000; 2026/27 is the last transitional year before the split kicks in.

A couple filling their cash ISA fully this year can protect £40,000. Over three years at 4.17% no-bonus, that compounds to £45,216 — all sheltered, all tax-free, all permanent. No future Chancellor can retrospectively tax what is already inside the wrapper.

Two deployment options worth real thought:

Split the allowance by tenor. Put £15,000 into an easy access ISA — Cynergy at 4.17% or Virgin Money at 4.15% — to cover your emergency buffer and any spending earmarked for 2026-27. Lock the remaining £5,000 in a two-year fix at 4.50-4.56%. You get flexibility on most of the money and rate protection on the portion you are genuinely certain you won't touch.

Front-load or drip-feed. If the money is ready, front-loading captures 12 months of interest on day one. If it isn't, drip-feeding avoids the classic mistake of sacrificing a competitive personal savings allowance position in a non-ISA account waiting for payday. Our debate on front-loading versus waiting until summer covers the trade-off in detail — the short answer is that front-loading wins on expected return, waiting wins on regret-aversion if rates rise later in the year.

Don't have £20,000? Put in what you can. Even £3,000 in a 4.17% ISA earns £125 tax-free, and the wrapper space is locked in forever. You can always transfer to a better rate later using the formal ISA transfer process — never withdraw and redeposit, or the money loses its tax-free status the instant it leaves the wrapper.

New money, disciplined enough to switch annually: Trading 212 at 4.62%. Set a calendar reminder for March 2027 — if you don't switch on time, you'll wake up on 4.62% and fall to 3.60% overnight. Over £20,000, that is a £204 income cut you will not notice until the year-end statement.

Transferring from old ISAs: Cynergy Bank at 4.17% is now the clear winner for transfers — 12 basis points higher than Leeds Building Society at 4.05% and without a bonus structure that applies only to new money. Trading 212's bonus excludes transfers of older-year money, which means a £40,000 transfer gets 3.60%, not 4.62%. Read the transfer mechanics carefully — the wrong move costs permanent tax-free status.

Set-and-forget savers: Cynergy Bank at 4.17%. Unlimited withdrawals, no bonus, no gotchas. The rate sits 42bp above base rate, FSCS-protected, and you will never receive a painful 'rate review' email.

Locking in certainty: Chetwood Bank 5-year at 4.55% if you believe the BoE will eventually cut back to 3%. Two-year fixes at 4.50-4.56% hit the sweet spot for most savers: long enough to ride out Iran-shock volatility, short enough to reprice into whatever the market looks like in April 2028.

Large balances (£50,000+): Split providers to stay inside the FSCS £120,000 limit. Open one easy access ISA for the 2026/27 allowance and transfer older pots into a separate provider. If your total ISA balance with any single banking licence tops £120,000, the excess is uninsured. And watch the Trading 212 edge case: its money sits at Barclays, NatWest, and JPMorgan, so your Trading 212 ISA stacks against direct savings with those banks.

Higher-rate taxpayers: The ISA is non-negotiable. The £500 PSA runs out at £11,990 of savings at Cynergy's rate. Every pound of interest above that threshold loses 40p to HMRC unless sheltered. At 4.17%, the shelter is worth £16.68 per £1,000 per year in avoided tax for a higher-rate taxpayer — and that saving compounds for every year the money stays in the wrapper.

Additional-rate taxpayers: No PSA, full stop. The ISA isn't optional — it's the only tax-free savings wrapper available to you. See our tax planning hub for the broader context, and for the structural choice between cash and equities inside the wrapper, the case for filling cash ISAs first and the case for putting every penny into equities give you both sides honestly.

Every rate in this guide is a snapshot. The direction of rates matters more.

Last autumn, the consensus was uncontroversial: the BoE would cut from 4.75% through 2025 and early 2026, bottoming near 3% by the end of 2026. The first half delivered — five cuts brought the base rate from 4.75% to 3.75% by December 2025. Then the Iran conflict escalated in February. Oil jumped. UK mortgage rates peaked. The MPC held unanimously in March 2026 citing energy-driven inflation risk. Market-implied pricing now expects the base rate to hold at 3.75% for the rest of 2026, with cuts resuming in 2027 if the energy shock eases.

The 10-year gilt yield tells the same story with less noise. Between August 2025 and February 2026 it sat in a 4.43-4.70% range. March's print at 4.70% — roughly the peak of the Iran-shock repricing — is why fixed ISA rates are now higher than easy access. Gilts at 4.70% give banks the raw material to offer 4.55% fixes without taking a margin hit. That pricing will reverse once gilts fall back, which is why the current window for fixing looks more attractive than it has in months.

For easy access savers the practical read is simpler: rates aren't collapsing this year. Trading 212 at 4.62% will likely persist through 2026 if the BoE stays on hold. Cynergy at 4.17% is stable. The February panic to lock in fixes before the BoE slashed rates has faded — but the residual yield premium in two-year fixes is still worth capturing for money you genuinely won't touch.

The next MPC decision is 30 April 2026. Markets are pricing essentially zero probability of a cut. A hawkish hold — or any hint that cuts have been pushed into 2027 — would probably push easy access rates up another 5-10 basis points as banks defend deposits. A dovish surprise, with the MPC signalling summer cuts, would cause fixes to reprice lower within days.

For the broader investing picture — whether a stocks and shares ISA should take priority over cash — the answer is mechanical. Cash ISAs are for money needed within five years. Anything beyond that horizon belongs in equities, where UK market history suggests a 4.5% real return — roughly 150 basis points above today's best cash ISA once inflation runs its usual erosion.

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