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If you turned 70½ in 2018 and you still haven't taken your first required minimum distribution from your individual retirement account, you're almost out of time. The IRS requires individuals holding retirement accounts such as IRAs and 401(k) plans to start taking withdrawals from those accounts by April 1 in the year after they've turned 70½. Each of these distributions is also taxable, so savers must also prepare to pay Uncle Sam. After you've made that first distribution, you must take subsequent RMDs in the following years by Dec. 31.

That means savers who are just now taking their 2018 distribution this spring must take a second withdrawal — this time for 2019 — by the end of this year. Failure to take the RMDs by the required date will result in a 50 percent excise tax on the amount you should have withdrawn. "The deadline for people who turned 70½ last year is less than a week away," said Martin Schamis, head of wealth planning at Janney Montgomery Scott, a broker-dealer in Philadelphia. "Once those RMDs begin, you don't really have much control over whether you take them or not," he said. "There isn't a lot you can do to lessen the tax hit that might be associated." Here's what you should know if you're new to these mandatory retirement account withdrawals.

Calculation flubs

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Perhaps the easiest way to botch your first RMD is to mistakenly take the wrong amount. Let's say that you own multiple IRAs and hold multiple 401(k) accounts at different employers. In that case, you need to calculate the RMD for each IRA separately each year. You can however, withdraw the total amount from just one of your IRAs. As for the 401(k) plans, you must calculate and take the RMD from each plan. "You can't take money from an IRA to satisfy an RMD on a 401(k)," said Ed Slott, CPA and founder of Ed Slott & Co. in Rockville Centre, New York.

Doubling up distributions

One error married couples tend to make is to take the distribution for both spouses from one account, said Slott. For instance, a husband with a large IRA might try to take the RMD for himself and his wife from that account, instead of letting her withdraw from her own IRA. More from Fixed Income Strategies:

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Medicare won't cover this key expense This move isn't permitted. Each spouse must take the RMD from his or her own respective account. "In this case, all the husband did was take too much from his IRA and not enough from his wife's account — and now she's subject to the 50 percent penalty," said Slott.

The No.1 misconception

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