Premium Bonds as a Savings Alternative: When the Numbers Actually Work in Your Favour
Premium Bonds are often compared to a lottery, but the real question for most savers is simpler: does the expected return beat a normal savings account once tax and luck are factored in?
A different question to ask
Most explainers on Premium Bonds focus on how the monthly prize draw works and what the odds of winning are. Those are worth understanding, but they are not the decision that actually matters to most people. The real question is: given what you could earn in a normal [savings account](/help-to-save-account-for-low-earners/ “il”), does it make sense to hold some or all of your money in Premium Bonds instead?
That depends on your tax position, how much you hold, how you feel about variance, and what else is available. This piece works through that decision rather than repeating the mechanics.
The prize fund rate is not your interest rate
NS&I publishes an annual ‘prize fund rate’ for Premium Bonds. It is easy to read this as if it were the interest rate on a savings account, but it isn’t. It is the average return across the entire pool of bonds if every prize were shared equally. In reality, most bondholders receive less than the prize fund rate in any given period, and a small number receive far more, including the two jackpot prizes each month. This is the core of why Premium Bonds behave like a lottery with a guaranteed capital return, rather than an interest-bearing account.
For decision-making purposes, treat the prize fund rate as an average outcome across millions of savers, not a personal promise. Your own result will be lumpier, especially with smaller holdings.
Why holding size changes the maths
The variance in Premium Bonds shrinks as you hold more bonds, because you are effectively buying more entries into the same draw. Someone holding a modest sum might go long stretches winning nothing, then get a windfall, then win nothing again. Someone holding close to the maximum allowed tends to see returns that track closer to the published prize fund rate over time, because they are represented across a much larger share of the prize pool.
This means Premium Bonds are structurally better suited to larger balances if your goal is a return close to the average. With a small holding, you are essentially accepting extra unpredictability without much extra prize-fund exposure to smooth it out.
The tax-free angle, and why it matters less than it used to
Premium Bond winnings are tax-free, which historically was a strong selling point for higher and additional rate taxpayers who lost a large chunk of savings interest to tax. That advantage still exists, but it needs to be weighed against the Personal Savings Allowance, which lets savers earn a certain amount of interest tax-free each year depending on their tax band. For many basic and higher rate taxpayers, ordinary savings interest up to the allowance is already tax-free, which narrows the gap between Premium Bonds and a standard easy-access or fixed-rate account.
If you are an additional rate taxpayer with no Personal Savings Allowance, or you have already used your allowance through other savings, the tax-free status of Premium Bonds carries more weight. Check your own allowance and tax band position with HMRC or MoneyHelper before assuming Premium Bonds are the more tax-efficient choice.
Comparing to a competitive savings account
A sensible way to decide is to compare the average, expected return from Premium Bonds (based on the current prize fund rate) against the best easy-access or fixed-rate savings deal you can actually get, after accounting for tax on the savings account interest if it exceeds your Personal Savings Allowance. If the guaranteed account clearly beats the expected Premium Bonds return, and you have no strong preference for the lottery element, a normal savings account is the more rational choice on average.
Where Premium Bonds tend to hold their own is when: you are already earning tax-free interest elsewhere and would exceed your Personal Savings Allowance by adding more; you want instant access without penalty; or you simply prefer the small chance of a large win over a certain but modest return, and you are comfortable that your capital is safe rather than growing at a guaranteed rate.
Capital security versus real returns
Both Premium Bonds and mainstream UK savings accounts benefit from strong protection: NS&I is backed by the UK government, and bank and building society deposits are protected up to the Financial Services Compensation Scheme limit per institution. Neither route puts your capital at meaningful risk in the way investing does. But ‘safe’ does not mean ‘growing’. With Premium Bonds, if you have a run of no wins, your capital sits still while inflation reduces its real value, exactly as it would in a very low-interest savings account.
A practical way to decide
Rather than asking whether Premium Bonds are ‘good’, ask three questions: what is the best guaranteed rate I can get elsewhere right now, would that guaranteed interest be taxed given my allowance, and how large is the sum I am considering holding. Small sums earmarked for a rainy day are usually better off in a competitive easy-access account, where the return is certain. Larger sums, particularly for taxpayers who would otherwise lose interest to tax, are where Premium Bonds become genuinely competitive rather than simply a fun alternative.
Check the current prize fund rate, savings rates and Personal Savings Allowance figures before deciding, since all three move over time and the comparison only works with up-to-date numbers.