Premium Bonds Calculator

Calculate your expected returns, win probabilities, and interest rate equivalents for NS&I Premium Bonds investments

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Expected Returns

Calculate median expected returns based on current 3.6% prize fund rate and your investment amount

Win Probabilities

Understand your chances of winning prizes each month with detailed statistical analysis

Prize Breakdown

See expected frequency of different prize amounts from £25 to £1 million

Interest Equivalent

Compare your expected Premium Bonds returns against traditional savings accounts

What Are Premium Bonds?

Premium Bonds are a savings product from NS&I (National Savings and Investments), backed by HM Treasury. Instead of paying guaranteed interest, Premium Bonds enter you into a monthly prize draw where you could win between £25 and £1 million - completely tax-free.

Key Features:

  • Minimum Investment: £25
  • Maximum Investment: £50,000
  • Prize Range: £25 to £1,000,000
  • Current Prize Fund Rate: 3.6%
  • Odds: 1 in 22,000 per £1 bond per month
  • Tax Status: All prizes are tax-free

How the Prize Draw Works

Each £1 bond you hold has a unique number and is entered into the monthly prize draw. ERNIE (Electronic Random Number Indicator Equipment) generates random numbers to select winning bonds. The more bonds you have, the better your chances - but there's no guarantee you'll win.

Expected Returns vs. Savings Accounts

While Premium Bonds offer the excitement of potential large prizes, the statistically expected return (median) is typically lower than the advertised prize fund rate. Our calculator helps you understand your realistic expected returns based on your investment amount.