The oldest of the baby boomers had an April tax deadline some almost certainly didn’t realize was approaching.

Unfortunately it was April 1, not the April 18 tax filing deadline. So if they did nothing they’ve already blown it. It’ll take a while, but one day they’ll get the letter from the Internal Revenue Service explaining how much they now owe, in that odd font the IRS uses that seems to come straight from the 1970s.

It will be, at least on a percentage basis, very painful — half of what was supposed to get withdrawn but wasn’t.

The April 1 deadline was for the first of what’s called a required minimum distribution from a tax-deferred plan for people who turned 70½ last year. A simpler way to say that is that people eventually need to start taking money from their IRA or 401(k)-type accounts, and the IRS decided to fix that date as April 1 of the year after they turned 70½.

The reason for requiring distributions is actually pretty simple. That money, all of it including the original money that went into the account, hasn’t already been taxed, and requiring it to come out of those tax-deferred accounts finally puts it on a tax return.

Why is all of the 401(k) money taxable? Because it’s money that was earned for paid work, or earned by investing that paycheck money. It’s going to be taxable whether you pay those taxes now or down the road.

If people think of 401(k) or IRA money as “tax-free,” they’ve fundamentally misunderstood a pretty simple idea. If people think they can hang onto that money and pass it tax free to heirs, they’ve also not got it right — but at least that’s a more complicated story.

Want to get out of paying income taxes on your 401(k) money? Giving it away to a genuine charity will work.

In the weeks leading up to the April 1 deadline for the first of the baby boomers to make the required withdrawal from the 401(k) account, the rhetoric about the looming required withdrawal grew a little heated on the internet. Even mainstream sites like MarketWatch included the required withdrawals on a list of “Five Big Tax Ripoffs That Should Be Repealed.”

When the Wall Street Journal covered the topic, it quoted a retiree complaining about the “unwanted income” that he was now forced to take as he finally reached the age of required withdrawals.

It wasn’t easy to read this with a straight face. If these retirees really didn’t want this income, several places came to mind that would’ve happily accepted it.

Then an e-mail on the issue came from a financial advisory firm in Edina called Capstone Advisory Group, a note that also talked of a “tax hike” and “forced retirement withdrawals.” Five minutes into a conversation this week with Capstone co-founder Greg Mortenson, though, and it was clear he wasn’t trying to advance the idea that required withdrawals somehow aren’t fair.

He’s an advocate of getting a lot smarter about what’s required of the tax code as it is. This e-mail about a tax hike was simply meant to be descriptive. Income taxes for retirees who start taking money from tax-deferred plans are likely going to increase, maybe by a lot. And savers needed to think this through well before they are required to start withdrawing money.

Most people understand that if 401(k) money comes out of an account before they get older, and the law fixes that half birthday at 59½, the taxpayer will get slapped with a penalty. Far fewer people seem to understand that withdrawals are going to someday be required, and that the whole amount will be taxable. “The majority of people … aren’t even aware that this is going to happen,” Mortenson said.

Capstone manages more than 50 companies’ retirement plans, and a lot of the workers in those plans are never going have the chance to hear about this from a financial planner. Some of the savvier ones can use Google to figure out the rules and do some planning, but most will reach retirement and find out their financial situation isn’t quite what they thought it was.

That’s why he’s been encouraging clients to do more education in their enrollment periods for 401(k) plans, and he also says that one session for the 22-year-olds to the 62-year-olds makes little sense. One Capstone client, with 400 or so workers in its plan, presents retirement finance information by age groups. This lets workers maybe five or so years away from retirement learn about things like the income they can expect from the retirement savings they’ve managed to put aside.

He sees another fundamental misunderstanding among clients, maybe just as worrisome. As he put it, “People are shocked at the amount of taxes they pay if 100 percent of their retirement income is coming from their retirement accounts. We have been told for decades that when you retire you are going to be in a lower tax bracket. Our experience is that is typically not going to be the case.”

So the problem here, as it always seems to be, is that retirees will reach their retirement and be unable to live as well as when they were working, with higher income taxes (and less money to spend) than they had counted on.

When he started in the financial advisory industry in the 1990s, a simple rule of thumb in financial planning was to make sure there was enough income in retirement to equal 70 percent of a worker’s last paycheck. To him the right planning number now seems closer to 100 percent of the last paycheck, “and definitely don’t plan on 70 or 75 percent,” he said.

The greatest retirement financial risk of all, of course, is outliving your money. Capstone has several hundred households as clients, Mortenson said, “and in the last two years we have celebrated three clients’ 100th birthday.” 612-673-4302