Scenario calculator
Premium Bonds Calculator
Estimate the chance of at least one Premium Bonds prize and the average expected prize value for a holding and period you choose. Calculations use the reviewed NS&I parameters shown below.
Your scenario
Enter a whole-pound amount from £25 to £50,000.
Period
Current model parameters: prize fund rate 4.35% and monthly odds 1 in 21,000 for each eligible £1 Bond. Effective September 2026; verified 9 September 2026. These values can change.
Estimated outcomes for your scenario
1 in 21,000Current odds
4.35%Prize Fund Rate
Not availableChance of at least one prize
Not availableChance of winning nothing
Not availableExpected number of prizes
Not availableExpected prize value
This is a statistical estimate, not a guaranteed return.
Choose a holding and period, then select Calculate.
Next step
Want to compare this prize-based scenario with quoted savings interest? Use the same holding and time period in our comparison.
Compare with savings →Track actual winnings →View latest results →