NS&I Premium Bonds at 3.30%: The Maths Has Changed — Here's Who Should Stay and Who Should Cash In

The 3.30% annual prize fund rate is not an interest rate. It's the percentage of the total bond fund that NS&I distributes as prizes each month. Your £1 Bonds enter a draw with odds of 23,000 to 1. Two people win £1 million every month. Everyone else is playing a lottery where the median outcome is zero.

Someone holding the maximum £50,000 can expect roughly £1,650 per year at average luck — down from £1,800 when the rate was 3.60%. A more typical £10,000 holding produces an expected £330 annually. But 'expected' is doing heavy lifting in that sentence. In any given month, most bondholders win nothing. The distribution is violently skewed towards a small number of large winners.

The critical comparison isn't Premium Bonds at 3.30% versus a <a href="/posts/fixed-rate-bonds-vs-easy-access-savings-where-to-park-your-cash-in-2026">savings account</a> at 4.75%. It's Premium Bonds at your actual expected return (probably below 3.30%) versus a savings account at your after-tax rate. That's where the calculation gets interesting.

Premium Bonds prizes are completely free from UK Income Tax and Capital Gains Tax. This is their only structural advantage — and for higher earners, it's enormous.

A basic-rate taxpayer gets a £1,000 Personal Savings Allowance (PSA). At the best easy-access rate of 4.75%, you'd need over £21,000 in savings before breaching that allowance and paying any tax on interest. Below that threshold, there's zero tax advantage to Premium Bonds — you're just accepting a lower, uncertain return for no benefit.

Higher-rate taxpayers get a £500 PSA. With £50,000 in a 4.75% account earning £2,375, they'd pay 40% tax on £1,875 above the allowance — that's £750 in tax, leaving a net return of £1,625. Premium Bonds' expected £1,650 is virtually identical, but guaranteed tax-free and without the HMRC paperwork.

Additional-rate taxpayers have no PSA at all. Every penny of savings interest is taxed at 45%. That £2,375 from a 4.75% account becomes just £1,306 after tax. Premium Bonds' expected £1,650 beats it by £344 per year — a pre-tax equivalent rate of roughly 6.00%.

The chart makes the case starkly. For basic-rate taxpayers, Premium Bonds lose to every alternative. For additional-rate taxpayers who've maxed their ISA, Premium Bonds win. The higher-rate bracket is the genuine toss-up.

Before moving any Premium Bonds money into a taxable savings account, use your ISA allowance first. The 2025/26 £20,000 ISA allowance expires on 5 April — two days from now — and you cannot carry it forward.

The best easy-access Cash ISAs are paying up to 4.68% tax-free. That's 4.68% guaranteed versus 3.30% expected (and likely less) from Premium Bonds. NS&I's own Direct ISA pays 3.50% — better than Premium Bonds with none of the lottery risk.

For a basic-rate taxpayer with £20,000: a <a href="/posts/cash-isa-rates-ranked-the-10-best-accounts-for-202526-and-what-they-actually">Cash ISA</a> at 4.68% returns £936 tax-free. Premium Bonds on £20,000 return an expected £660. That's £276 per year you're leaving on the table — and the ISA return is guaranteed while the Premium Bonds return is not.

The practical move for most people: cash in enough Premium Bonds to fill your ISA allowance before April 5, then reassess what to do with the remainder based on your tax position. NS&I processes withdrawals in 3-5 working days, so if you haven't started, today is effectively the deadline.

For more on the ISA deadline decision, see our ISA deadline guide and Cash ISA analysis.

NS&I has cut rates across the board, but the relative positioning of its products reveals where the value sits.

The NS&I Direct ISA at 3.50% pays more than Premium Bonds' expected return with zero luck involved — and it's still tax-free. If you want the Treasury-backed safety but don't care about the prize draw excitement, this is objectively the better product within NS&I's own range.

The Direct Saver at 3.05% is hard to justify when the best easy-access accounts pay 4.75% elsewhere. The only advantage is 100% government backing with no limit — the FSCS covers £120,000 per person per institution at banks, but NS&I has no cap. For someone with very large cash holdings, that matters.

CPI inflation was 3.0% in February 2026, and the Bank of England expects it to rise to around 3.5% in March, driven by energy prices linked to the Middle East conflict. At 3.30%, Premium Bonds are now delivering a real return of approximately zero for average-luck holders — and a real loss for the majority who win below the expected amount.

Through 2024, Premium Bonds sat comfortably above inflation — the real return was positive even for below-average-luck holders. That cushion has disappeared. The rate dropped from 4.0% to 3.60% in October 2025, then to 3.30% from April 2026, while inflation climbed from 2.0% to 3.0%.

The Bank of England held rates at 3.75% in March, with markets pricing further cuts through 2026. This creates a paradox: the base rate falls are what prompted NS&I's cuts, but they also mean savings rates across the market will drift lower. The window to lock in a 4.5%+ fixed rate is narrowing.

Answer three questions:

1. Have you used your £20,000 ISA allowance? If no, move Premium Bonds money into a Cash ISA before April 5. A 4.68% tax-free ISA beats 3.30% expected Premium Bonds in every scenario, regardless of tax bracket. This is the easiest win in UK savings.

2. What's your marginal tax rate? Basic rate (20%) with savings under £21,000 outside ISAs: cash in Premium Bonds, open a savings account at 4.75%. You'll pay no tax on the interest thanks to the £1,000 PSA. Higher rate (40%): run the numbers — it's close. Additional rate (45%): keep Premium Bonds for any cash above your ISA.

3. Do you have more than £120,000 in cash? The FSCS covers £120,000 per person per institution. NS&I is 100% Treasury-backed with no limit. If you hold very large cash balances, Premium Bonds' unlimited government guarantee is a genuine safety advantage.

For further analysis of Premium Bonds alternatives, see our savings hub and Premium Bonds vs Cash ISA comparison.

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