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ERNIE, our Electronic Random Number Indicator Equipment, is the power behind Premium Bonds. Generating the numbers for 491 million tax-free prizes worth approximately £20.9 billion.

The next generation

The power behind Premium Bonds has now been upgraded to the next generation – ERNIE 5. Unlike previous versions which used thermal noise to produce random numbers, ERNIE 5 is powered by quantum technology, which uses light. This new technology allows ERNIE to produce enough random numbers for a monthly prize draw in just 12 minutes – 42.5 times faster than its thermal predecessor at the end of its number-generating career.

The genius of ERNIE

The clever bit

Using light, ERNIE 5 generates random numbers that are matched against eligible Bond numbers to determine the lucky winners. And because it’s random, every Bond number, whether it has 8, 9, 10 or 11 digits, has a separate and equal chance of winning a prize.

Ernie in action

One in a million

Our Agents Million have the important task of delivering the winning news in person to the two monthly jackpot winners. Since the first Premium Bonds millionaire in 1994, over 400 new millionaires have been paid a visit.

Proud heritage

A Bletchley Park code breaker invented the first ERNIE in 1956. Following this, Harold Macmillan announced the launch of Premium Bonds on Budget Day, 17 April 1956, offering everyone an alternative way to save. Since then, there have been five generations of ERNIE and with continuous advances in technology, each has become faster and more powerful.


Premium Bonds today

There are now more ways than ever to check, manage and buy Premium Bonds. Anyone can see if they have won a prize by using our online prize checker or app. And of course you can buy more Bonds whenever you like, 24 hours a day.

Ernie 3

Got a question about your Existing Bonds or need to update your details ?

Common Myths

Common myths

ERNIE is so famous that he receives Christmas and Valentine cards every year. He’s even gone on display at The Science Museum. Like many celebrity figures, over the years myths have grown up around ERNIE and Premium Bonds. Here are a few of them debunked.

  • Myth: ERNIE isn’t really random

    Each month, the Government Actuary's Department (GAD) does an independent check to ensure ERNIE's output is random. GAD then issues a certificate to confirm that it has no reason to believe the draw isn't random. We can only publish numbers and pay out prizes when that certificate has been issued.

  • Myth: You have to have £50,000 invested to win the jackpot

    Jackpot winners have a varied amount invested – one winner of the £1 million jackpot only had £17 in Premium Bonds! However, the more Bonds you hold, the better your chances of winning.

  • Myth: Only new Bonds win prizes

    Each £1 Bond has an equal chance of winning, regardless of when or where it was bought. Over 95% of eligible Bonds have been bought since the year 2000. So even though Premium Bonds have been on sale for over 60 years, this is why newer Bonds seem to win more frequently.

  • Myth: Old Bonds are left out of the draw

    As numbers aren’t entered into ERNIE, there’s no way any Bonds can be left out of the draw. ERNIE generates the winning numbers randomly and then we match them against eligible Bonds.

  • Myth: Only Bonds from the South East win prizes

    If it seems that more prizes are won by holders in the South East, that's because there are more Bonds held there compared with the rest of the UK.

  • Myth: The more Bonds sold, the smaller my chances of winning

    Not at all. The prize fund for each draw is a month's interest on all eligible Bonds in the draw, so the more Bonds we sell, the bigger the prize fund.