Retirement Financial Decision Modeling

How this engine works

You enter your own figures; the engine models two scenarios side by side and shows the twelve-month difference between them. The outputs are estimates built from your inputs and documented assumptions — not predictions, and not advice. Mood and stress are self-reported context that adjust the wording of the summary, nothing else. Inputs are processed in your browser. The full methodology, including what the engine does not claim, is on the Decision Center.

Step 2: Decision Forge — compare assumptions

Decision scenarios with reflection prompts

Each scenario in the tool above presents two options drawn from this event and models them side by side from the figures you entered. Before the comparison, the page names a cognitive-bias concept as an educational reflection prompt. It is a general prompt attached to the scenario rather than a finding about you: the page does not test whether the concept applies to your situation, and it does not indicate which option you should choose.

Self-reported context at decision time

The page does not create a psychological profile. Mood and stress may tailor wording and general next-step suggestions. They do not change the entered financial values or scenario math. They do not establish decision readiness. The named bias concept is a general reflection prompt; the page does not detect bias, assess decision capacity, diagnose a condition, or predict outcomes.

The enrolment windows that do not reopen

Retirement is mostly a series of choices you can revisit later. These four are not. Two of them attach a surcharge to your Medicare premium for the rest of your life, one is counted in days from the moment money leaves an account, and none can be reopened by explaining what happened.

The 2026 contribution limits

The Roth catch-up rule is in force for 2026

This provision is misreported more often than any other in retirement saving, and the mistake has one specific cause. The final regulations carry an applicability date of taxable years beginning after 31 December 2026, and that date gets read as the date the rule itself begins. It is not. The statute has applied to taxable years beginning after 31 December 2023; the administrative transition that suspended it covered only 2024 and 2025 and expired on 31 December 2025. For 2026 the requirement is live, administered under a reasonable, good-faith standard until the regulations themselves apply (IRS, Notice 2023-62).

What it requires: if you are 50 or older and your 2025 Social Security wages from the employer sponsoring the plan exceeded $150,000, your 2026 catch-up contributions must be made as Roth. The IRS set that threshold expressly to determine whether catch-up contributions for 2026 must be designated Roth (Notice 2025-67). It is a prior-year test, so it is already settled for this year — the figure to check is Box 3 of your 2025 W-2, not what you expect to earn now.

Two further details worth knowing before you plan around it: the test is per employer, so changing jobs resets it, and someone self-employed with no such wages is outside it entirely. Collectively bargained multiemployer plans have a genuine reprieve, running until the first taxable year after the last agreement in effect on 17 November 2025 terminates.

Required distributions

The required beginning age is 73. Your first distribution is due by 1 April of the year after you reach it — and the second is due by 31 December of that same year, which means taking two in one calendar year and stacking the income. Taking the first one in the year you turn 73 avoids that.

Three points that correct common claims. The age is not 75 — that is scheduled only for people reaching 74 after 2032 and is not in force. The penalty is 25 percent, reduced to 10 percent if corrected within two years, not the 50 percent that older guidance describes. And Roth 401(k) and 403(b) accounts no longer have lifetime required distributions, which removed the main reason people used to roll them to a Roth IRA; beneficiaries of Roth accounts are still subject to distribution rules.

If you are still working past 73, a workplace plan at your current employer can generally wait until you retire — unless you own five percent or more of the business. That exception does not apply to IRAs, which must begin regardless.

Social Security in 2026

Medicare, and the lookback that catches new retirees

The 2026 Part B standard premium is $202.90 a month with a $283 annual deductible; the Part A inpatient deductible is $1,736 per benefit period.

The part that surprises people is the income-related surcharge. It begins above $109,000 of modified adjusted gross income for an individual, or $218,000 filing jointly, adding $81.20 a month at the first tier — and it is calculated on a two-year lookback. Your 2026 premium is based on the return you filed in 2025 for tax year 2024.

So someone who retired last year can be paying a surcharge based on their final full working year, which is precisely when income was highest. There is a remedy: a life-changing event, including work stoppage or work reduction, lets you ask for the surcharge to be recalculated on current income rather than the old return. It requires a form and it is not automatic, and it is one of the more valuable pieces of paperwork available in the first year of retirement.

The withdrawal rate: three numbers that are not three answers

You will see 4 percent, 4.7 percent and 3.9 percent quoted as competing safe withdrawal rates. They are not competing, because they measure different things — and stacking them side by side is misleading even when each is quoted correctly.

None of these is a government figure, and none is a rule. The honest use of them is as a starting point that you revisit, rather than a number you set once and defend for three decades. The variable that moves the answer most is not the percentage — it is whether you are willing to spend less in bad years.