First RMD Calculator: Take It by December 31, or Delay to April 1?

Updated August 2, 2026. Quick answer: your first required distribution is the only one you are allowed to postpone — to April 1 of the following year. Almost nobody should. Postponing does not skip a distribution; it stacks two into one tax year, and because the balance was never reduced, the second one is bigger as well. The cost ranges from trivial to thousands depending entirely on where your income sits against a bracket line.

Both paths, on your numbers

The rule, and the trap inside it

The statute sets your required beginning date as “April 1 of the calendar year following the later of—(I) the calendar year in which the employee attains the applicable age, or (II) the calendar year in which the employee retires”. That second limb is the still-working exception, and it does not apply to IRAs — where it does apply, and to which account.

The trap is that the deadline for every subsequent distribution is unchanged: “The required minimum distribution for any year after the year you reach age 73 must be made by December 31 of that later year.” The IRS spells the collision out with its own example: “If you reach age 73 in 2024, you must take your first RMD by April 1, 2025, and the second RMD by Dec. 31, 2025.” Two distributions, one tax year.

The second effect, which the tax tables do not show you

Distributions are computed on the previous December 31 balance. Take the first one on time and the account is smaller when next year’s figure is struck. Delay it and the account goes into the new year intact, so the second distribution is computed on a larger number.

Run with no growth at all, purely to isolate the effect: on the example above the second distribution comes out $1,372 larger simply because the first was postponed. Delaying does not defer the money. It enlarges it and moves it next to another one.

How much this actually costs

Less than people fear, and more than they notice. A $500,000 balance at 73 with $60,000 of other income, filing jointly: delaying costs about $99 across the two years. That is a rounding error, and if cash flow genuinely needs the delay, take it.

A $2,500,000 balance at 73 with $200,000 of other income, filing single: delaying costs about $5,211. Same rule, same decision, a different order of magnitude — because the stacked year pushes through a bracket.

Which is the actual lesson. The question is never “is delaying bad”; it is “where does my stacked year land”. For most people the answer is a modest cost. For anyone near a line it is not modest at all, and the two-year Medicare lag means a year that crosses one is billed long after it stops feeling connected — the lookback and why the tiers are cliffs rather than ramps.

What this does not decide

Which account the money comes out of, if you have several. That is its own rule and it is genuinely counter-intuitive: IRAs can be aggregated and 401(k)s cannot — each plan must pay its own. Getting this wrong is the most common way to under-distribute while believing you complied.

Whether you owe one at all this year: the age rules, 73 now and 75 later, and what happens in the year you actually retire. If one was already missed, the penalty is lower than it used to be if you fix it inside the window.

And the two moves that pair with a first distribution: using the December distribution to carry your whole year’s withholding, which is the most under-used trick available to a retiree, and why a conversion cannot come first. Beneficiaries are a different rulebook entirely — inherited accounts do not use this table.

Required beginning date from 26 U.S.C. § 401(a)(9)(C)(i); the applicable ages from § 401(a)(9)(C)(v); the Uniform Lifetime Table from 26 CFR § 1.401(a)(9)-9(c); the computation rule, the subsequent-year deadline and the two-in-one-year example from IRS Publication 590-B and the IRS RMD FAQs. Tax figures use the 2026 brackets and standard deduction from IRS Rev. Proc. 2025-32. Read August 2026. General information, not tax advice.