UPDATE: |How NS&I Premium Bonds holders can calculate how much they are likely to win News

An online tool can help you work out how much you could win with Premium Bonds – and how lucky you are if you’ve already won

Every month National Savings and Investments (NS&I) creates two new millionaires when their monthly prizes are announced.

As well as the top prize of £1 millionaire, there are £100,000, £50,000, £25,000, £5,000, £1,000, £500, £100, £50 and £25 prizes handed out to people with their money invested in a Premium Bonds account.

Premium Bond saving accounts do not accrue interest, rather the prizes shared out each month equate to an interest rate. Although the NS&I announced that the interest rate has reduced from April (from 4 per cent to 3.8 per cent), the savings provider has confirmed that the number of prizes won will remain the same.

In April 2025, two people received the top £1 million prize, 78 people won £100,000 and 158 people won £50,000.

To be in with a chance of winning a cash prize in the Premium Bond draw each month, you must have invested some money into an NS&I account. You can open an account with as little as £25, and the highest amount you can invest is £50,000.

Every £1 in your account is worth one bond, which is tied to a code. At the beginning of each month, the NS&I’s random number generator ERNIE picks a selection of codes which creates that month’s winners.

So technically, the more money you have in your Premium Bond account, the higher your chances of winning – but some people have been lucky and won high cash prizes without having the maximum amount of savings.

In April, one lucky saver from Leeds, West Yorkshire, won £100,000 with just £2,000 in their account. And another person won £25,000 with just £1 worth of Premium Bonds.

Premium Bonds were introduced back in November 1956 by Prime Minister Harold Macmillan’s government as a way to encourage saving, with the added excitement of a prize draw as opposed to earning traditional interest.

But if you are considering opening an NS&I Premium Bonds account and want to know the realistic likelihood of winning big, there is a handy online tool to do just that.

MoneySavingExpert, founded by financial expert Martin Lewis, has a Premium Bonds Calculator which you can use to work out how much ‘interest’ you might get on your savings, based on probabilities and interest rates.

There are two tabs – the first one helps you to work out how much you might win by inputting the amount of money you are planning to invest in a Premium Bond account, then you can choose a time period, and there is an option to compare it to other savings methods.

If you invest £10,000 in your Premium Bond account, the MSE calculator says: “With average luck, you would expect to win roughly £650 over 2 years if you have £10,000 of Premium Bonds.”

The calculator uses an estimate of the “median average” which means if everyone with £1,000 in bonds stood in ascending order of amount won, the person in the middle of the line has “average luck”.

You can also work out how lucky you are on a scale from “unlucky” to “very lucky” depending on how much you have won compared to the amount of Premium Bonds you own. The saver from Leeds who won £100,000 from £2,000 worth of Premium Bonds comes out as “very lucky”.

The calculator isn’t a guarantee of how much you will save by investing in Premium Bonds as the chances of winning relies on the automatic number generator.

You can find MoneySavingExpert’s Premium Bond Calculator on its website.