The prize fund rate, explained
Understand why the Premium Bonds prize fund rate is different from a guaranteed return, with a worked example and links to NS&I.
Read the guideA little help with the numbers
Premium Bonds guides
Practical explanations of your odds, the prize fund rate and your results, with worked examples and official sources.
Your chances of winning
See how a Premium Bonds holding changes the chance of winning, why winning nothing can be ordinary, and how to use our free odds calculator.
Read the guideWhen your Bonds become eligible
Understand the full calendar month waiting period for new Premium Bonds, with month-end examples and the rule for automatically reinvested prizes.
Read the guideHow your luck score works
Compare your Premium Bonds prizes with expected winnings. Learn how your luck score works, how to record changing balances and how your figures stay private.
Read the guideCalculation methods and official NS&I sources are linked in each guide. Reviewed 21 October 2026. We are independent of NS&I.