Premium Bonds calculator
See your chance of a Premium Bonds prize each month and year, the average and typical prizes on what you hold, and how they compare with an easy access account.
- Typical prizes over 1 year
- £350
- Half of holders win £350 or less. The average is £435, which is what the 4.35% prize fund rate pays out, but 68% of holders get less than that.
- Chance of a prize each month
- 37.9%
- £10,000 of £1 Bonds at 21,000 to 1 each
- Chance of a prize in a year
- 99.7%
- at least one in 12 draws
- Average prizes a year
- £435
- 4.35% of £10,000
- Easy access account
- £375
- over 1 year at 3.75% after tax
- Chance prizes beat the account
- 41.7%
- after tax, over 1 year
- Chance of no prize at all
- 0.3%
- over 1 year
3.9% of holders won more than £900, off the right of the chart.
Show how the simulated holders did
| Holders | Won this or less over 1 year |
|---|---|
| 1 in 10 | £150 |
| 1 in 4 | £225 |
| Half | £350 |
| 3 in 4 | £475 |
| 9 in 10 | £650 |
Uses NS&I's prize fund rate of 4.35% and odds of 21,000 to 1 for each £1 Bond, with the mix of prizes in the September 2026 draw, checked on 28 September 2026. All three can change at any time. The chances and the average are worked out exactly. The typical prize and the spread come from simulating 20,000 holders with a fixed random seed, so the same numbers always give the same answer. Prizes are taken out rather than reinvested, and the easy access interest is the rate you enter for the time held, also taken out. New Bonds wait a whole month before their first draw, which this leaves out. Prizes are free of UK Income Tax and Capital Gains Tax, so the easy access account is compared after tax, at the rate you enter. NS&I Direct Saver's 3.75% is before tax: you keep all of it while the interest is within your Personal Savings Allowance, and 2.25% as a higher rate taxpayer who has used it.
What goes in
Enter how much you hold in Premium Bonds, from £25 to £50,000, how many months to look at, and the rate an easy access account would pay you after tax, since prizes are tax-free. It starts at 3.75%, NS&I’s own Direct Saver rate before tax from 18 August 2026. You keep all of it while the interest is within your Personal Savings Allowance. A higher rate taxpayer who has used their allowance pays 40% on it and keeps 2.25%.
Average and typical prizes
Premium Bonds don’t pay interest. Each £1 Bond goes into a monthly draw at odds of 21,000 to 1, and the prizes add up to the prize fund rate, 4.35% a year from the September 2026 draw. That rate is an average across every Bond, big prizes included. Most holders never win a big one, so most get less than the average.
The September 2026 draw had 6,529,868 prizes worth £497,086,175, and 6,446,807 of them were £25, £50 or £100. On £10,000 the average is £435 a year, but the typical holder, halfway down the list, wins £350, and 68% of holders get less than the average. At 3.75% after tax the account pays £375, and prizes beat that in 41.7% of the simulated years.
How it works it out
The chance of a prize is exact, since each £1 Bond has a 1 in 21,000 chance every month. For the typical result, the calculator simulates 20,000 holders, gives each winning Bond a prize from the September 2026 mix, and takes the middle total. NS&I can change the rate, the odds and the prizes at any time. Prizes are free of UK Income Tax and Capital Gains Tax, and new Bonds wait a whole month before their first draw.