Understanding RMDs: How Required Minimum Distributions Affect Your Tax Bill

A Tucson gentleman called me last year, a little rattled. He’d just turned 73, his accountant had mentioned “required distributions,” and he wanted to know one thing: “How much do I actually have to take out, and why does it feel like it’s going to wreck my tax return?” He’d spent forty years dutifully saving in his 401(k) and rolling it into an IRA. Nobody had ever explained that the IRS was eventually going to want its share, on its schedule, not his.

If you’ve built a sizable traditional IRA or 401(k), this is one of the most important retirement-tax topics you can understand. Required minimum distributions (RMDs) are the government’s way of finally collecting tax on all those pre-tax dollars you set aside. And for Arizona retirees with $1 million to $3 million or more in pre-tax accounts, RMDs can quietly reshape your tax picture for the rest of your life.

What an RMD Is and When It Starts

An RMD is the minimum amount you’re required to withdraw each year from tax-deferred retirement accounts once you reach a certain age. The money comes out, and the withdrawn amount is generally taxed as ordinary income.

Under current rules, RMDs begin at age 73 for most people retiring now, and the starting age rises to 75 for those born in 1960 or later. Roth IRAs, by contrast, have no RMDs during your lifetime, which is one reason they’re such a powerful planning tool.

The required amount is calculated each year by dividing your account balance (as of the end of the prior year) by a life-expectancy factor from an IRS table. The older you get, the larger the percentage you’re required to withdraw. You can always take out more than the minimum, but taking less than required has historically carried a stiff penalty, so this isn’t a deadline to miss. You can estimate your own required amount with our RMD calculator.

How RMDs Stack on Top of Your Other Income

Here’s the part that catches people off guard. RMDs don’t exist in a vacuum, they stack on top of everything else you’re already reporting: Social Security, pension income, interest, dividends, capital gains, and any other withdrawals.

Imagine a couple in Chandler comfortably living on Social Security and a modest pension, sitting in a low bracket. Then RMDs begin on a large IRA, and suddenly there’s a substantial chunk of additional ordinary income landing on top of their existing income. That added income can:

• Push them into a higher marginal tax bracket.
• Cause more of their Social Security benefits to become taxable.
• Increase the tax on their long-term capital gains and qualified dividends.

This is why I tell clients that the size of your future RMD is really determined by the planning you do before it begins. By the time the distributions start, your options narrow considerably.

The IRMAA Ripple Effect

RMDs don’t just affect your income tax, they can ripple into your Medicare premiums through something called IRMAA (the Income-Related Monthly Adjustment Amount).

If your income climbs above certain thresholds, you pay surcharges on top of your standard Medicare Part B and Part D premiums. There are two things that make IRMAA especially sneaky:

• It’s based on your income from two years prior, so a big RMD year today can raise your Medicare premiums two years down the road, often when you’ve forgotten why.
• It works like a cliff, not a gradual slope. Going even one dollar over a threshold can bump you into a higher surcharge tier for the entire year.

For a retired couple in Phoenix or Mesa, a poorly planned RMD can mean hundreds of extra dollars per person, per month in Medicare premiums, on top of the income tax. That’s a real cost worth managing proactively.

Levers You Can Pull to Soften the Hit

The good news is that RMDs are predictable, which means they’re plannable. Here are the main levers I work through with clients.

Draw Down Pre-Tax Accounts Early

The years between retirement and your RMD start age are golden. By taking strategic withdrawals or doing partial Roth conversions in those lower-income years, you reduce the pre-tax balance that future RMDs are calculated on. Smaller balance, smaller required distribution, smaller tax bill later. The trade-offs are worth modeling with a tax-efficient withdrawal calculator before you commit to a path.

Qualified Charitable Distributions (QCDs)

If you’re charitably inclined, QCDs are one of the cleanest tools available. Starting at age 70½, you can direct money straight from your IRA to a qualified charity. A QCD can count toward satisfying your RMD, but the amount sent to charity is excluded from your taxable income entirely.

That exclusion is the magic. Because the dollars never show up in your adjusted gross income, a QCD can lower your income taxes, reduce the taxation of your Social Security, and help keep you under those IRMAA thresholds, all at once. For retirees who give to their church, alma mater, or a local Arizona charity anyway, giving through a QCD is almost always more tax-efficient than writing a check from your checking account.

Coordinate, Don’t Isolate

The biggest mistake is treating the RMD as a standalone chore, just pull the number and pay the tax. A better approach coordinates RMDs with Social Security timing, capital gains, charitable giving, and your overall withdrawal sequence. This is the kind of integrated, multi-year planning that a fee-only fiduciary advisor can build with you, with no product to sell and no commission riding on the outcome.

A Quick Word on Timing and Heirs

Two practical notes. First, your very first RMD can be delayed to April 1 of the year after you turn 73, but doing so forces two RMDs into the same calendar year, which often creates a bigger tax spike, not a smaller one. Usually it’s cleaner to take the first one on time. Second, most non-spouse heirs who inherit an IRA must now empty it within ten years, which can dump large taxable distributions onto your children during their peak earning years. That’s yet another reason to think about drawing down pre-tax accounts thoughtfully while you’re alive.

The Bottom Line

RMDs are predictable, which makes them manageable, but only if you plan ahead. Understanding when they start, how they stack on your other income, how they ripple into Medicare premiums, and how tools like QCDs can ease the burden puts you back in control of your own tax bill. If you’d like help projecting your future RMDs and building a strategy to keep them from quietly eroding your retirement, connect with a fee-only fiduciary advisor in Arizona who can map it all out with you.

Important Disclosures

This material is intended for informational and educational purposes only and should not be construed as individualized investment, tax, or legal advice. Consult your own qualified advisor before acting on anything discussed here.

Investing involves risk, including possible loss of principal. Tax rules change and outcomes vary by individual circumstances. Arizona Fee Only is a directory and does not provide investment, tax, or legal advice.