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CombinatoricsMay 1, 20264 min read

The 1-in-292-Million Number

Where Powerball's jackpot odds actually come from — a two-line derivation that explains everything.

If you've ever heard "1 in 292 million" and wondered where the number comes from, it isn't a marketing figure or an actuarial estimate. It's a precise count of the outcome space, derivable in two lines of high-school combinatorics.

The two pools

Powerball asks you to pick:

  • 5 white balls from 1 through 69, in any order.
  • 1 red Powerball from 1 through 26, independent of the white balls.

Because order doesn't matter for the white balls and the Powerball is independent, the total number of distinct tickets is the white-ball combinations multiplied by the Powerball options.

The arithmetic

White-ball combinations:
C(69, 5) = 69! / (5! · 64!) = 11,238,513

Total combinations: 11,238,513 × 26 = 292,201,338

That's it. The denominator of your jackpot probability is the size of the combinatorial space. Any single ticket has exactly one chance in that many of matching.

What this means in practice

Jackpot odds of 1 in 292,201,338 mean that to be 95% likely to win at least once, you'd need to buy approximately 875 million tickets. At $2 each, that's $1.75 billion in tickets — for a jackpot that's almost always much less. The expected value is sharply negative for any reasonable single play.

Why the number is fixed, not estimated

Some games quote approximate odds because their prize structures involve continuous random variables (scratch-density, response times). Powerball is a pure combinatorial draw — 5 distinct integers from a labeled urn of 69, plus 1 from an urn of 26. The denominator is a count, not a measurement. Anyone with a calculator can verify it.

The Mega Millions comparison

After the April 2025 redesign, Mega Millions uses C(70,5) × 24:

C(70, 5) = 12,103,014
Total: 12,103,014 × 24 = 290,472,336

Mega Millions is now marginally easier to win the jackpot than Powerball — by about 1.8 million combinations. Practically indistinguishable; both are vanishingly rare. The interesting fact is that the redesign was calibrated precisely to nudge MM ahead of Powerball on jackpot odds while raising the ticket price — a calibration of perceived value, not actual value.

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