US
Lottery Number Lab Odds, drawing history and probability for Mega Millions and Powerball

Reference

Lottery terms, defined

The jargon on tickets, press releases and this site, in plain English. Linked where a longer explanation exists.

Annuity
The advertised jackpot paid as 30 instalments over 29 years, each 5% larger than the last. Most winners take the cash option instead.
Cash option / lump sum
A single payment equal to the present value of the annuity, typically around half the advertised jackpot, all taxable in one year.
Matrix
The ball pools: how many white balls, from what range, plus the size of the bonus pool. Written 5/70 + 1/24 for current Mega Millions.
Mega Ball
The gold bonus ball in Mega Millions, drawn from a separate machine. Currently 1–24.
Powerball (the ball)
The red bonus ball in Powerball, currently 1–26, independent of the five white balls.
Megaplier
The retired $1 Mega Millions add-on that multiplied non-jackpot prizes. Replaced in April 2025 by a built-in 2X–10X multiplier on every $5 play.
Power Play
An optional $1 Powerball add-on that multiplies most non-jackpot prizes by 2X–10X. The $1 million tier is capped at $2 million.
Rollover
What happens when nobody wins the jackpot: the prize is added to the next drawing. Harder jackpot odds produce longer rolls and larger advertised prizes.
Independent trials
Each drawing is a new experiment. Previous outcomes do not change the probability of the next one.
Expected value
The average result of a bet if it were repeated forever: each prize times its probability, summed. For these jackpots it is almost always below the ticket price once cash discount, tax and sharing are included.
Withholding vs tax owed
US lotteries withhold 24% federal tax on large prizes. That is a prepayment. A jackpot is generally taxed at 37% federal, so more is usually due at filing, plus any state tax.
Overall odds
The chance of winning any prize, not just the jackpot — about 1 in 23 for Mega Millions and 1 in 25 for Powerball. Most of those wins are a few dollars.
White balls
The five main numbers. Order does not matter; they are published sorted.
Era / matrix change
A date when the ball pools changed. Statistics on this site never mix drawings from different matrices.

For how the odds themselves are counted, see how to calculate lottery odds. For the 24% / 37% tax split, see record jackpots and taxes.