When a lottery jackpot grows to hundreds of millions or even billions of dollars, it stirs up excitement. But when you dig deeper, the odds are actually much lower than you might think.

Lottery can be a good source of revenue for states, as long as the prize amounts are reasonable. But when the jackpot is too high, it can discourage ticket sales, which is why some states have decreased or increased the number of balls in the game. It’s important for people to know the odds before they buy a ticket.

If you play the Powerball or Mega Millions lottery, your chances of winning are greater because there is a larger pool of numbers to choose from than in state and local games. But you also pay a higher prize tax rate, which can make your winnings smaller than you might expect. You can opt for a lump sum or annuity payment, which will determine how quickly you receive your prize.

It’s tempting to pick the numbers that have meaning to you, such as birthdays or other personal numbers. But Clotfelter says it’s a bad idea, as the digits will repeat in a predictable way and reduce your odds of winning. Instead, he says, choose numbers that aren’t consecutive and don’t end in similar digits. Also, don’t pick all odd or all even numbers, as only 3% of the lottery numbers have ever been both. Ideally, you should have three of one and two of the other.