Tax on a $100,000 Roth conversion by other income
The Roth conversion stacks on top of whatever else you earn that year, so the same $100,000 costs more when other income has already used the low brackets. Other income here is pension or wage-like ordinary income; age 60, no state tax.
| Other income | Single | Married filing jointly |
|---|---|---|
| $0 | $13,170 (13.2%) | $7,640 (7.6%) |
| $25,000 | $17,844 (17.8%) | $10,640 (10.6%) |
| $50,000 | $20,914 (20.9%) | $13,560 (13.6%) |
| $100,000 | $23,564 (23.6%) | $18,700 (18.7%) |
| $150,000 | $26,570 (26.6%) | $22,128 (22.1%) |
By age
A conversion owes no 10% penalty at any age. From 65 the standard deduction is larger and the senior deduction (2025 to 2028) lowers the tax, until income phases it out.
| Age | Federal income tax | Total |
|---|---|---|
| 50 | $13,170 | $13,170 |
| 60 | $13,170 | $13,170 |
| 66 | $11,729 | $11,729 |
| 73 | $11,729 | $11,729 |
By state
State tax on the same Roth conversion, single, 60, no other income. The nine states with no income tax take nothing. Colorado is left out: whether a conversion counts toward its pension subtraction is not settled in its published guidance.
| State | State tax | Share of the Roth conversion |
|---|---|---|
| Arizona | $2,098 | 2.1% |
| California | $4,911 | 4.9% |
| Maryland | $4,386 | 4.4% |
| Massachusetts | $4,780 | 4.8% |
| Michigan | $1,126 | 1.1% |
| North Carolina | $3,481 | 3.5% |
| Ohio | $2,313 | 2.3% |
| Pennsylvania | $0 | 0.0% |
| Virginia | $4,936 | 4.9% |
Spread over several years
Taking the same $100,000 in equal parts over more years keeps more of it in lower brackets. Total federal tax, single, 60:
| Taken over | No other income | $50,000 of other income a year |
|---|---|---|
| One year | $13,170 | $20,914 |
| 2 years ($50,000 a year) | $7,640 | $18,700 |
| 4 years ($25,000 a year) | $3,560 | $15,400 |
Medicare premiums and the five-year rule
A conversion raises modified AGI, which sets Medicare premiums two years later. For a married couple both 65 with $40,000 of Social Security and $30,000 of IRA withdrawals, a $100,000 conversion adds about $15,424 of federal tax and no IRMAA surcharge. Converted dollars withdrawn within five years before 59½ owe the 10% penalty, which is what a Roth conversion ladder plans around. The Roth conversion calculator shows how much fits in each bracket.
Other amounts
| Amount | 401(k) withdrawal | Roth conversion |
|---|---|---|
| $25,000 | $890 on $25,000 | $890 on $25,000 |
| $50,000 | $3,820 on $50,000 | $3,820 on $50,000 |
| $100,000 | $13,170 on $100,000 | $13,170 |
| $200,000 | $36,734 on $200,000 | $36,734 on $200,000 |
The calculator, set to this Roth conversion
Set to a single filer aged 60 with $100,000 of Roth conversion and nothing else. Add Social Security, a pension, your state or a spouse.
On $100,000 of income, the 2026 tax is about $13,170: $13,170 federal. $0 of your Social Security is taxable. The next $1,000 you withdraw from an IRA would cost $220 in tax.
This year’s income sets your Medicare premiums for 2028. See your IRMAA tier.
Figures checked on against IRS Rev. Proc. 2025-32, 2026 inflation adjustments (PDF), IRS, enhanced deduction for seniors (26 U.S.C. 151(d)(5)(C)) and IRS Publication 575, Pension and Annuity Income.