Premium Bonds Calculator
Estimate your expected Premium Bonds prize winnings, probability of at least one prize per month, and the equivalent interest rate.
How Premium Bonds Calculator works
How Premium Bonds work
NS&I holds a monthly prize draw. Each £1 bond gives you one entry per month. Prizes range from £25 to £1 million. All prizes are tax-free. There is no interest — prizes are your return. The prize fund rate (equivalent AER) is set by NS&I and changes periodically.
Expected value
The expected annual prize winnings = Holding × Prize Fund Rate. At 4.40% on £10,000: £440 expected per year. However, actual winnings vary widely — you could win much more or nothing at all in a given period. Expected value is mathematically identical to the prize fund rate.
Premium Bonds vs savings accounts
For basic-rate taxpayers with savings under their Personal Savings Allowance, a taxable savings account at the same or higher rate beats Premium Bonds. For higher-rate taxpayers, the tax-free prize fund is more competitive. For those with large holdings, the £85,000 FSCS limit does not apply — NS&I is backed by HM Treasury.
Frequently asked questions
What is the Premium Bonds prize rate?
As of April 2025, the prize fund rate is 4.40% tax-free (equivalent AER). The odds of any one bond winning in a month are 1 in 21,000. NS&I adjusts the rate periodically in line with interest rate changes.
Are Premium Bonds better than a savings account?
It depends on your tax position and luck. The expected value is equal to the prize fund rate. For basic-rate taxpayers within their PSA, a savings account at the same rate gives a guaranteed equivalent return. For higher-rate taxpayers or those with very large sums, the tax-free element can make Premium Bonds more attractive.
What is the maximum Premium Bonds holding?
£50,000 per person. The minimum purchase is £25. Bonds are registered in your name and are protected without limit by HM Treasury (NS&I is a government-backed institution).
How long does it take to win on Premium Bonds?
Based on probability, a £1,000 holding has roughly a 4.8% chance of winning each month (about 1 win per 21 months). A £10,000 holding has ~38% chance each month. Chance-based — some people win frequently, others less often.
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