Close Your web browser is out of date. Updating your browser will improve how you can view and use this website. Find out how to do this



Play Video


Who is ERNIE?

Our Electronic Random Number Indicator Equipment, or ERNIE, was invented by one of the original Bletchley Park code breakers in 1956. Since then, he’s generated the numbers for 426 million tax-free prizes worth approximately £19 billion.

The genius of ERNIE

The basic function of ERNIE hasn’t changed over the years. ERNIE generates numbers completely at random.

The genius of ERNIE

The clever bit

ERNIE 4 generates Bond numbers completely at random, no matter how long. So 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

Drum roll please

When ERNIE has randomly generated a list of numbers they're matched in order against eligible Bond numbers to determine the lucky winners.


Moving with the times

Since 1957, there have been four generations of ERNIE. With continuous advances in technology, each has become faster and smaller. If ERNIE 1 were still in use today, it would take over 100 days to complete a draw. Our current ERNIE 4 only takes around 5 hours!

Ernie 3

A bit of history

On Budget day, 17 April 1956, Harold Macmillan announced the launch of Premium Bonds. His intention was to reduce inflation and offer an alternative way to save.

First Premium Bond sold

Alderman Sir Cuthbert Ackroyd, the Lord Mayor of London, bought the first Premium Bond on 1 November 1956. By the end of that first day, £5 million worth had been sold. With £82 million invested, it was time for the first draw on Saturday 1 June 1957. There were 23,000 prizes in that first draw with a top prize of £1,000.

Ernie 1st bond sold

Agent Million

Our Agents Million deliver good news in person to the two jackpot winners. One Agent Million has told over 100 new millionaires about their good fortune.

Ernie Advertising

Premium Bonds today

Since 2010 we've given you more ways to manage and check your 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 today

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. When ERNIE randomly generates winners, he doesn’t store any numbers, so there’s no way any Bonds can be left out.

  • Myth: Old Bonds are left out of the draw

    Winning numbers are generated randomly and then matched against eligible Bond numbers afterwards – numbers aren't entered into or stored in ERNIE so there's no way that any Bonds can be left out of the draw.

  • 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.