Premium Bonds Calculator

Estimate your expected NS&I Premium Bonds winnings and your odds of winning a prize.

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Your Premium Bonds Holding
£
Min £25, max £50,000
%
How this is calculated

Each £1 Bond is one independent entry into the monthly prize draw, with a 1-in-"odds" chance of winning. The "expected winnings per year" simply applies the prize fund rate to your holding, exactly as NS&I design the system to work on average. The win probabilities use the standard formula for "at least one success": 1 - (1 - 1/odds)number of bonds, applied per month and per year.

This is a simplification - it doesn't model the actual distribution of prize sizes (from £25 up to £1 million), only the probability of winning something and the average pound value of what you'd expect to win over time.

Quick Facts
  • All prizes are tax-free, from £25 to £1 million.
  • Odds are the same for every Bond, however many you hold.
  • Minimum holding £25, maximum £50,000 per person.
  • You can withdraw your original capital at any time.
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Frequently Asked Questions

Instead of paying interest, NS&I puts an amount equivalent to a notional annual interest rate - the "prize fund rate" - into a monthly prize draw pot each month. As of the September 2026 draw, NS&I set this rate at 4.35% with odds of 21,000 to 1 per £1 Bond. Both the rate and the odds change from time to time, so the fields on this calculator are editable - check nsandi.com for the current figures before relying on the result.

Each eligible £1 Bond number has a 1 in 21,000 (at the current odds) chance of winning a prize in any given month's draw, regardless of how many Bonds you hold or how long you've held them. Holding more Bonds buys you more entries into the same draw, not better odds per entry.

No. It is a statistical average based on the prize fund rate, assuming perfectly average luck over a long enough period. In reality, prizes are random and lumpy - most prizes are £25, but a small number of much larger prizes (up to the £1 million jackpot) skew the average upward. NS&I themselves note that you typically need well over £10,000-£40,000 in Bonds to have a realistic chance of achieving close to the average rate over time; smaller holdings often win less than the headline rate suggests, and some win nothing at all in a given year.

Yes. All Premium Bonds prizes, including the £1 million jackpot, are completely free of UK Income Tax and Capital Gains Tax, and winnings don't need to be declared on a tax return.

The minimum purchase is £25, and the maximum any one person can hold is £50,000. Each whole £1 invested is one Bond number and one entry into the monthly draw.