About the UK Premium Bonds Calculator
This Premium Bonds calculator estimates what your NS&I Premium Bonds are likely to win. Enter how much you hold and over how many months, and it shows the average (expected) prizes, the typical (median) result most holders actually get, a lucky 90th-percentile outcome, your chance of winning at least one prize, and the taxable savings rate that would match Premium Bonds for your tax band.
Premium Bonds pay no interest. Instead, the interest on the whole pool funds a monthly prize draw. NS&I currently quotes a prize fund rate of 4.35% and odds of 21,000 to 1 for each £1 bond in each monthly draw, with prizes from £25 to £1 million. This calculator uses the actual prize allocation for the October 2026 draw — about 6.5 million prizes worth £498 million — so the shape of your possible winnings reflects how NS&I really shares out prizes.
Because a few huge prizes pull the average up, most holders win less than the prize fund rate suggests: the median return is below the average, and with small holdings it is often zero. Prizes are tax-free, which makes Premium Bonds more attractive to higher- and additional-rate taxpayers who have used their Personal Savings Allowance. You can hold from £25 up to £50,000, and bonds must be held for a full calendar month before entering a draw.
With the default inputs, the expected (average) prizes is £435.00. Change any value above to recalculate instantly.
How to use the uk premium bonds calculator
- 1Enter how much you hold in Premium Bonds (up to £50,000).
- 2Choose how many monthly draws to look at — 12 for a year.
- 3Keep the current 21,000-to-1 odds or update them from NS&I.
- 4Pick your tax rate to compare with a taxable savings account.
- 5Compare the expected and typical (median) winnings before deciding how much to hold.
Formula and method
Each £1 bond has a 1-in-odds chance of winning in each monthly draw, so the number of prizes you win is very close to a Poisson distribution with mean λ = holding × draws ÷ odds. Multiplying λ by the average prize in the current allocation (about £76.12) gives your expected winnings, which is the same as the prize fund rate applied to your holding.
The typical (median) and lucky (90th-percentile) outcomes come from the full distribution of total winnings: the number of prizes is Poisson and each prize value is drawn from NS&I’s published allocation (£25 to £1 million). The calculator computes that distribution exactly with Panjer’s recursion on £25 steps. The taxable-equivalent rate is prize fund rate ÷ (1 − your tax rate), because prizes are tax-free.
- λ
- Expected number of prizes over the period
- Odds
- Odds per £1 bond per monthly draw (21,000)
- Average prize
- Total prize fund ÷ number of prizes in the draw
Worked examples
£10,000 for a year
With £10,000 you expect about 5.7 prizes a year and £435 on average (4.35%). Half of holders win £350 or less, and one in ten wins £675 or more. For a 40% taxpayer that average is worth the same as 7.25% on a taxable account.
Maximum £50,000 holding
The maximum holding expects about 28.6 prizes and £2,175 a year. The median is £1,900 — a typical return of 3.8% rather than 4.35% — because rare big prizes lift the average.
Small £1,000 holding
With £1,000 the expected winnings are £43.50 a year, but the chance of winning anything at all is only about 44%, so the median result is £0. A one-in-ten lucky year brings £100 or more.
Frequently asked questions
What are the current Premium Bonds odds?+
NS&I quotes odds of 21,000 to 1 for each £1 bond in each monthly draw, with a prize fund rate of 4.35%. Both are variable and NS&I changes them from time to time, so check the current figures before relying on the result.
How much will I win with £50,000 in Premium Bonds?+
At a 4.35% prize fund rate the average is about £2,175 a year, but the typical (median) holder of £50,000 wins around £1,900, because a handful of very large prizes pull the average up.
Are Premium Bond prizes taxable?+
No. Premium Bond prizes are free of UK Income Tax and Capital Gains Tax, and they do not use your Personal Savings Allowance. That makes them relatively more attractive if you pay higher-rate tax on savings interest.
Are Premium Bonds better than a savings account?+
It depends on your tax rate and your luck. With average luck, the prize fund rate is tax-free, so compare it with your after-tax savings rate. Most holders win less than average, and inflation erodes the capital, so a top savings account often pays more for basic-rate taxpayers.
How soon do new Premium Bonds enter the draw?+
Bonds must be held for a whole calendar month before they are eligible. For example, bonds bought at any time in November enter the January draw.
Is my money safe in Premium Bonds?+
Yes. NS&I is backed by HM Treasury, so 100% of the money you hold in Premium Bonds is secure. You can cash them in at any time without penalty.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.