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Sources and calculations

Where the figures come from

Official draw results, clear calculation methods and how your figures stay private.

Official NS&I results

Draw history is available from January 2025 – October 2026. Every prize table is checked against NS&I’s published prize count and total winnings.

Last checked 21 October 2026. The latest draw included is October 2026. Results are updated after NS&I publishes a new draw.

View all 22 monthly sources

The winning-number statistics cover a separate period, July–October 2026. They use NS&I’s winning-number downloads, with the prize totals checked against each month’s announcement.

Prize counts refer to individual prizes. One saver can win more than one.

How expected winnings are calculated

Expected winnings are the average prize amount for your eligible balance. For each month, we divide the total prize money by the number of £1 Bonds in the draw, then multiply by your balance.

Expected winnings = eligible balance × total prize money ÷ £1 Bonds in the draw

“Past draws” uses the published figures for each month you select. “Same odds” uses one selected month’s prize fund and odds throughout. Neither option predicts future rates or winnings.

A single prize total assumes your balance stayed the same. If it changed, enter monthly amounts so each balance counts for the right period. Prizes are not automatically added to your balance.

What your luck score means

Luck score = 100 × your winnings ÷ expected winnings

A score of 100 matches the average. A score of 150 means you won 50% more than expected. It does not mean you were luckier than a particular percentage of savers.

Large prizes pull the average up. A result below average, or even no prizes, can be normal, especially with a smaller balance. The chance estimate beside your score helps put that result in context.

For a period, we compare your total winnings with the total expected amount. We don’t average individual monthly scores. A blank month means winnings haven’t been entered; £0 means you won nothing. Your score appears once all selected months have been entered and your expected amount is above £0.

Past wins or losses don’t change your next draw’s chances. This calculator doesn’t check Bond numbers or confirm that a prize is owed. Check your prizes with NS&I.

Understanding the chance estimates

The chance of winning nothing uses the number of eligible Bonds, the number of prizes and your balance for each draw. Each month is treated as a separate draw.

Estimates for total winnings account for the different prize sizes and their chances. The middle result is called the median. The typical range shown contains around 8 in 10 estimated results. These figures are estimates, not a promise of what you’ll win.

More about the statistical method

No-prize probabilities use a finite-population calculation: each £1 Bond is assumed to receive at most one prize in a draw. Total-prize estimates use a compound Poisson approximation, combining the published prize sizes and their chances across your selected months.

A chance described as “this amount or less” or “this amount or more” includes results equal to that amount. The lower and upper limits of the typical range are the estimated 10th and 90th percentiles. They describe possible winnings, not a ranking of savers.

The last bar in the odds chart includes all higher winnings, including rare large prizes. Very large entered totals may be beyond the range where we can provide a reliable chance estimate; the luck score can still compare that total with the average.

Data reuse and independence

Contains public sector information licensed under the Open Government Licence v3.0. Source: National Savings and Investments (NS&I). See NS&I’s public-information reuse policy.

PremiumBonds.io is independent of NS&I and is not endorsed by it. Draw tables and number statistics use public results. They do not include saver names, account details or addresses.

Always refer to NS&I for product terms, eligibility, official prizes and claims.