Best savings accounts UK: choose access and after-tax yield, not the headline AER

Put the same £10,000 in either account today, leave it untouched for 12 months and assume Direct Saver's variable rate stays at 3.75% throughout. The fixed bond pays £499 gross at maturity; Direct Saver would pay approximately £375 gross if its rate stays unchanged. NS&I says the bond cannot be withdrawn during its term; Direct Saver permits withdrawals without notice or penalty. The chart also shows an illustrative case in which the whole year's interest is taxed at 40% because the saver has already used their Personal Savings Allowance elsewhere. It is not a forecast or a universal net yield.

The fixed-rate premium is £124 gross, or £74.40 if every pound of interest is taxed at 40%. For a higher-rate saver with £250 of allowance remaining, net interest would instead be £325 on the easy-access example (£375 − 40% × £125) and £399.40 on the fix (£499 − 40% × £249): still £74.40 apart because the same £250 shelter applies to both. An emergency withdrawal could cost far more than that differential if the money is locked away. See the savings hub for account types before choosing a provider.

HMRC explains that interest across taxable accounts is added together and that ISA interest is usually tax-free. HMRC’s allowance table shows the Personal Savings Allowance is £1,000 for basic-rate taxpayers, £500 for higher-rate taxpayers and £0 for additional-rate taxpayers; HMRC counts savings interest when determining your tax band, so check your total income and other interest before assigning an allowance to a new account. Some low-income savers also qualify for the starting rate for savings or unused Personal Allowance. At £10,000, if no other interest uses the allowance, neither example crosses a basic- or higher-rate saver's allowance on its own. The gross numbers above are then the relevant amounts.

A cash ISA could beat a taxable account even with a lower headline rate once the allowance is exhausted. If all interest is taxable at 40%, a taxable 4.99% fix nets 2.994% on the assumptions above; a tax-free cash ISA paying more than 2.994% over the same one-year term and access conditions would pay more net interest. This is a break-even illustration, not a claim about an available ISA offer. Compare matched terms, and use the savings tax calculator to put your other interest into the calculation. Our ISA guide explains the wrapper; check the current ISA subscription rules before transferring existing savings.

Tax is assessed by tax year, not by a rolling 12-month chart. NS&I says bond interest is taxable in the tax year the bond matures, whereas Direct Saver credits interest yearly. Depending on your opening date, payment date, other income and other accounts, the relevant remaining allowance could differ; these illustrations assume the same available allowance at the time interest is taxed. The starting rate for savings may also change your personal result.

An easy-access rate with a temporary bonus is not comparable to a year-long fixed AER merely by reading today's headline. Hypothetical arithmetic, not an advertised offer: if an account pays the equivalent of 4.50% annually for six months then 3.00% for six months, £10,000 earns about £375 over the year under a simple half-year interest approximation, before compounding and tax — not £450. A bonus expiring after six months leaves you exposed to the underlying rate; a variable underlying rate can also change. Check the provider's summary box for the end date, minimum balance and withdrawal rules, then put a reminder in your calendar.

The Direct Saver product page explicitly calls its 3.75% rate variable; the one-year bond's summary box fixes 4.99% for Issue 93 but warns an issue can be withdrawn from sale. Neither justifies predicting a full year's easy-access yield. If you need the money on a particular date, compare the exact maturity date, not simply the quoted AER. For a middle ground, read our notice-account guide only if you can genuinely wait out the notice period.

FSCS confirms eligible deposits at UK-authorised banks, building societies and credit unions are covered up to £120,000 per eligible person per banking licence (since 1 December 2025). Two brands sharing a licence share that limit; it is not a separate £120,000 for every savings account. Check the licence before splitting a large balance. NS&I is government-backed rather than a bank deposit under the FSCS bank scheme: do not describe its protection as another FSCS allowance.

Put emergency money in access cash first, then compare genuinely spare money across fixes and cash ISAs using after-tax interest on the same deposit and horizon. The extra £124 gross in this dated NS&I example is only attractive if you can afford to forgo withdrawals for a full year. See our cash ISA versus savings account discussion for the wrapper decision, but verify any offer on the provider's own current terms before applying.