Stop Gambling Your Savings on Premium Bonds: A Cash ISA Pays £276 More Per Year, Guaranteed

Let's put real numbers side by side. The Bank of England base rate was held at 3.75% on 19 March 2026, unchanged since December 2025. The best easy-access cash ISA rates are currently 4.68%, with fixed-rate options at 4.35%.

Premium Bonds? The prize fund rate is 3.60% until the March 2026 draw, then drops to 3.30% from April. The odds of each £1 bond winning any prize are currently 22,000 to 1, worsening to 23,000 to 1 from April.

Here's what that means for your money:

Amount	Cash ISA (4.68%)	Premium Bonds (3.30% from April)	Annual difference
£10,000	£468 guaranteed	~£330 average	£138
£20,000	£936 guaranteed	~£660 average	£276
£50,000	£2,340 guaranteed	~£1,650 average	£690

The word "guaranteed" is doing a lot of heavy lifting in that table. Your cash ISA pays that figure, full stop, every year. Premium Bonds might pay more, might pay less, might pay nothing at all. Over 12 months, most bondholders will receive a handful of £25 prizes and precious little else.

Premium Bonds' biggest selling point is that prizes are "tax-free." This is true — but it's also completely irrelevant for most savers, because cash ISA interest is also tax-free. Every pound of interest, with no cap, no limit, and no dependency on your tax bracket.

Here's what Premium Bond marketing conveniently omits: you don't need Premium Bonds to avoid tax on savings. The Personal Savings Allowance already gives basic-rate taxpayers £1,000 of tax-free interest on ordinary savings, and higher-rate taxpayers get £500. And inside a cash ISA, there is no limit at all — every penny of interest is tax-free forever.

So the honest comparison isn't "tax-free Premium Bonds vs taxable savings accounts." It's "tax-free Premium Bonds at 3.30% vs tax-free cash ISAs at 4.68%." Framed correctly, Premium Bonds lose on every metric that matters.

The only savers for whom Premium Bonds have a genuine tax advantage are additional-rate taxpayers (45%) with savings exceeding their £20,000 ISA allowance who have already used their £0 PSA. That's a vanishingly small group, and even they would be better served by exploring other tax-efficient options.

NS&I structures Premium Bonds as a prize draw rather than a savings product for one reason: it makes people accept lower returns in exchange for excitement. Behavioural economists call this "probability weighting" — humans systematically overvalue small chances of large gains. It's the same cognitive bias that sells lottery tickets.

Think about what you're actually doing when you buy Premium Bonds. You're accepting a 3.30% average return — with the possibility of earning 0% — because there's a 1 in 53.6 billion chance your bond wins £1 million in any given month. You're volunteering for worse returns because NS&I has gamified your savings account.

The median Premium Bonds holder with £20,000 invested will win approximately 10 to 12 prizes per year, virtually all of them £25. That's £250-£300. Not the £660 "average" — that average is skewed upward by the rare large prizes (£100,000 and £1 million) that you will almost certainly never win.

Here's a thought experiment that clarifies the absurdity. Imagine your bank offered you two accounts: one pays 4.68% interest, deposited monthly like clockwork. The other pays an "average" of 3.30%, but the actual amount varies randomly each month and you might receive nothing at all. Which would you choose? The question answers itself — yet 23 million people hold Premium Bonds.

A cash ISA doesn't need to trick you into accepting worse returns. It just pays you 4.68%, every month, in predictable interest you can see in your account. No draws, no odds, no hoping.

NS&I has already announced the prize fund rate drops from 3.60% to 3.30% in April 2026. This isn't a one-off — it follows the direction of the Bank of England base rate, which has fallen from its 5.25% peak in August 2023 to 3.75% today.

But here's the critical difference: cash ISA rates from competitive providers tend to hold above the base rate because banks are fighting for deposits. The best easy-access cash ISAs are paying 4.68% against a 3.75% base rate — that's 93 basis points above base. Premium Bonds, by contrast, are falling to 45 basis points below base rate.

The gap between the two has been widening steadily. In early 2024, it was roughly 0.4 percentage points. By April 2026, it's 1.38 percentage points. On £50,000, that's the difference between earning £2,340 in guaranteed cash ISA interest and hoping for approximately £1,650 in random prizes.

NS&I doesn't compete for deposits like commercial banks do — it has a government-set funding remit. When the Treasury wants less retail funding, NS&I cuts rates. Commercial banks, by contrast, are actively competing for your cash ISA deposits because they need retail funding. That structural difference is why the gap keeps widening, and it's unlikely to close any time soon. Even the NS&I Direct ISA only pays 3.50% — a full 1.18 percentage points below the market leaders.

If you're holding Premium Bonds and this article has you rethinking, here's the practical path:

Step 1: Check your actual returns. Log into NS&I and look at your prize history for the last 12 months. Divide total prizes by your holding to get your actual return. Most people are shocked at how far below the "average" they fall.

Step 2: Open a cash ISA. You can use up to £20,000 of ISA allowance per tax year. If you haven't used any of your 2025/26 allowance, you have until 5 April to shelter £20,000 in a cash ISA at today's rates. See our cash ISA comparison for the current best deals.

Step 3: Cash out Premium Bonds. NS&I processes withdrawals within a few working days. The money hits your bank account, and you can transfer it into your new cash ISA. Any bonds withdrawn after the monthly draw date are excluded from that month's draw — so time it after the draw if you want one last roll of the dice.

Step 4: For amounts above £20,000, you'll need to wait until the new tax year (6 April) for a fresh ISA allowance, or consider high-interest savings accounts where the Personal Savings Allowance shelters the first £1,000 (basic rate) or £500 (higher rate) of interest.

Holding Premium Bonds above your ISA allowance is more defensible — but only for higher-rate taxpayers. For basic-rate taxpayers, even a standard savings account at 4.5% beats Premium Bonds at 3.30% after the PSA is factored in.

One final point: don't let the maximum £50,000 Premium Bonds holding limit fool you into thinking it's a serious wealth-building tool. The ISA allowance is £20,000 per year, but your ISA pot has no upper limit — you can accumulate hundreds of thousands over time, all earning tax-free interest. Premium Bonds cap you at £50,000 total, earning a mediocre rate. The ISA is the product designed for long-term savers. Premium Bonds are designed for people who like opening letters from NS&I.

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

<p>For related guidance, see our article on <a href="/posts/premium-bonds-beat-cash-isas-for-one-simple-reason-youll-never-owe-hmrc-a-penny">the tax argument that makes Premium Bonds unbeatable</a>.</p>