Premium Bonds Odds Calculator
Discover your exact statistical chances of winning an NS&I Premium Bonds prize. Estimate monthly and annual odds based on your total holding.
Calculate Your Winning Chances
Enter your total Premium Bonds holding amount to instantly see your statistical probability of winning a prize in any given monthly draw.
Premium Bonds Odds Estimator
Calculate your probability based on current NS&I odds (21,000 to 1).
How the Odds Work
Understanding NS&I probability
Per £1 Bond Basis
Every £1 you invest equals one bond. Each bond has an independent 21,000 to 1 chance of winning a prize in the monthly draw.
Cumulative Probability
The more bonds you hold, the higher your overall chance. The calculator uses the exact formula: 1 - (20999/21000)^Bonds.
ERNIE’s Random Selection
Winners are chosen by ERNIE (Electronic Random Number Indicator Equipment), which is independently audited to ensure absolute fairness and randomness.
Odds by Holding Amount
A general overview of your statistical chances of winning at least one prize in a single monthly draw, based on common holding amounts.
| Total Holding | Number of Bonds | Monthly Chance of Winning | Expected Wins Per Year |
|---|---|---|---|
| £100 | 100 | 0.48% | ~0.06 |
| £500 | 500 | 2.35% | ~0.29 |
| £1,000 | 1,000 | 4.65% | ~0.57 |
| £5,000 | 5,000 | 21.25% | ~2.86 |
| £10,000 | 10,000 | 38.05% | ~5.71 |
| £50,000 (Max) | 50,000 | 90.85% | ~28.57 |
Premium Bonds FAQ
Answers to the most frequently asked questions about NS&I Premium Bonds odds, prizes, and rules.
The current odds of winning any prize are 21,000 to 1 against per £1 bond per monthly draw. This means for every £1,000 you hold, you have roughly a 4.6% chance of winning at least one prize in a given month.
No. All Premium Bonds prizes are completely tax-free in the UK. You do not need to declare any winnings on your Self Assessment tax return, and they are free from Income Tax and Capital Gains Tax.
The maximum holding limit for Premium Bonds is £50,000 per person. This equals 50,000 individual £1 bonds, giving you the highest possible statistical chance of winning in each monthly draw.
The monthly draws are conducted by ERNIE (Electronic Random Number Indicator Equipment), which generates random numbers to select winning bonds. ERNIE is independently audited to ensure every £1 bond has an exactly equal chance of winning.