While it's anyone's guess who will end up winning the Mega Millions and Powerball jackpots, there's at least one guaranteed recipient of a chunk of the loot — the IRS. With the Mega Millions jackpot at $1.6 billion and Powerball's top prize at $620 million, that tax bill will be hefty even if the winner employs strategies to reduce their taxable income. "If you have a win of, say, $100,000, it's easier to minimize the tax burden," said Cari Weston, director of tax practice and ethics for the American Institute of CPAs. "But when it's this kind of win, it's going to be harder."

A customer holds Mega Millions tickets at a newsstand in midtown Manhattan in New York, U.S., October 19, 2018. Mike Segar | Reuters

The $1.6 billion up for grabs in Mega Millions marks the largest jackpot in lottery history. Your chance of winning it is pretty dismal: 1 in 302.6 million. For the Powerball jackpot, meanwhile, your chance of winning is 1 in 292 million. The chance of winning both lotteries is at least 1 in 88 quadrillion (that's 88 followed by 15 zeros). The next drawings are Tuesday night for Mega Millions and Wednesday night for Powerball. If you happen to beat the astronomical odds and hit all winning numbers in either game, be aware that the taxation of your prize starts before even reaching you. Whether you take your haul as a lump sum or as an annuity spread out over three decades, your win is reduced by a 24 percent federal tax withholding (prior to 2018, the withholding rate was 25 percent).

The immediate cash option for Mega Millions is $904 million. The federal withholding would reduce that by $217 million. For the $354.3 million Powerball lump sum, it would mean $85 million getting shaved off the top. "I see the withholding as a good thing," Weston said. "When people come into a lot of money all at once, the last thing they're thinking about is their taxes." However, that's just the start of what you'd owe. The top income tax rate for individuals is 37 percent (down from 39.6 percent prior to 2018). That rate applies to adjusted gross income of $500,000 or more. In other words, hitting either jackpot would mean facing that top rate. You would still owe any difference between that initial withholding and the amount generated by applying that tax rate to your income.

Top 10 lottery jackpots Rank Amount Date won Game Winner locations 1 $1.586 billion Jan. 13, 2016 Powerball CA, FL, TN 2 $1.54 billion Oct. 23, 2018 Mega Millions SC 3 $758.7 million Aug. 23, 2017 Powerball MA 4 $656 million Mar. 30, 2012 Mega Millions KS, IL, MD 5 $648 million Dec. 17, 2013 Mega Millions CA, GA 6 $620 million ??? Powerball ??? 7 $590.5 million 18-May-13 Powerball FL 8 $587.5 million Nov. 28, 2012 Powerball AZ, MO 9 $564.1 million Feb. 11, 2015 Powerball NC, PR, TX 10 $559.7 million Jan. 6, 2018 Powerball NH

"The key is to be strategic at the front end so you're ready when tax time comes around," Weston said. On top of the federal withholding, you'll owe state taxes on the money unless you live where lottery wins are untaxed. For states that do take a piece, the rate ranges from a high of 8.82 percent in New York to a low of 2.9 percent in North Dakota, according to lottery site USAMega.com. Translation: You might pay north of 45 percent altogether in taxes, depending on where you purchased the ticket and where you live.