See your taxes before and after you retire.

The gap years

For many households the lowest-tax years come right after the paychecks stop. Wages are gone, Social Security has not started, and required withdrawals are years away. If spending comes from savings during that stretch, taxable income can fall to a fraction of what it was.

That is the window when some households look at partial Roth conversions: paying tax on part of a traditional IRA at a lower rate now, so that less is taxed later, when Social Security and required withdrawals stack on top. Whether that trade makes sense depends on future tax rates, how long the money stays invested, and who inherits it.

Your last paychecks can set your first Medicare premiums

Medicare's income surcharge, called IRMAA, is generally based on the tax return from two years earlier, so premiums at 65 usually follow income at 63. A final year of salary, a bonus or a severance payment can push that year over a line, and the surcharge arrives after the paycheck has stopped.

Social Security can make a new determination after a work stoppage or work reduction, two of eight life-changing events, using Form SSA-44. A Roth conversion or a large capital gain is not on that list, so a conversion in the years just before Medicare carries that possible cost too.

Why the next $1,000 can cost more than your bracket

Once Social Security starts, each added dollar of other income can make up to 85 more cents of benefits taxable, so a 12% bracket can behave like a 22% one. For 2025 through 2028, the new $6,000 deduction for people 65 and older also shrinks by 6 cents for every dollar of income above $75,000, or $150,000 on a joint return.

The planner runs each stage again with $1,000 added and reports the actual difference in federal tax, so those effects show up instead of hiding behind the bracket rate.

When required withdrawals begin

Required minimum distributions from traditional IRAs generally begin at 73 for people born from 1951 through 1959 and at 75 for people born in 1960 or later. The first year's amount is the prior year-end balance divided by a figure from the IRS Uniform Lifetime Table.

The planner divides today's balance by that figure, with no growth assumed, to show the scale of the first withdrawal, and shows how gap-year conversions would shrink it. It is a reference point, not a projection of any account's value.

How to read the numbers

Each stage is one representative year at 2026 federal figures, so later years read in today's dollars: brackets, Medicare lines and Social Security are all shown in this year's terms. The $6,000 senior deduction is counted only for years through 2028, when it is scheduled to end. In the gap years the planner assumes spending comes from traditional IRA or 401(k) withdrawals; spending from cash or a taxable account would leave more room. Both spouses are assumed to claim Social Security at the same age.

It covers federal income tax on ordinary income only. It does not include state income tax, capital gains or qualified dividends, the net investment income tax, itemized deductions, credits, or the alternative minimum tax. Treat the results as a way to frame questions for your tax professional and advisor, not as an answer.

2026 federal tax brackets

2026 IRMAA tiers

Questions people ask

What are the gap years before Social Security?

They are the years between leaving work and claiming Social Security. Without wages or benefits, taxable income often drops sharply, which can leave room in the lower tax brackets. Some households use that room for withdrawals or partial Roth conversions; whether that fits depends on their circumstances.

Does my income at 63 affect my Medicare premiums?

Generally, yes. Social Security sets the Medicare income surcharge, IRMAA, from the most recent tax return the IRS can provide, which is usually from two years before the premium year. Income at 63 typically sets premiums at 65. A work stoppage or work reduction can support a request for a new determination.

What are the 2026 IRMAA income thresholds?

For 2026, the Medicare income surcharge begins above $109,000 of modified adjusted gross income on an individual return and above $218,000 on a joint return. The standard Part B premium is $202.90 a month, and the five surcharge tiers raise it to between $284.10 and $689.90 per person.

Does a Roth conversion count toward IRMAA?

Generally, yes. The taxable amount of a Roth conversion is included in adjusted gross income, the starting point for the modified adjusted gross income Social Security uses for IRMAA. A conversion is not one of the life-changing events that can support a request for a new determination.

How much Social Security is taxable?

Up to 85 percent of benefits can be taxable. The share depends on provisional income: your other income, plus tax-exempt interest, plus half of your benefits. The base amounts are $25,000 and $34,000 for single filers and $32,000 and $44,000 for joint filers, and they are not adjusted for inflation.

When do required minimum distributions start?

Under current law, generally at age 73 for people born from 1951 through 1959 and at age 75 for people born in 1960 or later. The first distribution can be delayed until April 1 of the following year, but the second is still due by December 31 of that year.

Primary sources

• IRS Rev. Proc. 2025-32: 2026 brackets and standard deduction
• IRS: enhanced deduction for seniors
• IRS Publication 915: Social Security benefits
• CMS: 2026 Medicare Parts B and D premiums
• Social Security: modified adjusted gross income for IRMAA
• IRS Publication 590-B: required minimum distributions

Want someone to look at your plan?

This planner shows the arithmetic. A retirement plan also weighs your investments, cash needs, state taxes and the years ahead. The first step is a free, thirty-minute intake call with Ian Bearss. The call is not advice; its purpose is to understand your situation and connect you with an advisor.