Tax on a $40,000 Roth conversion by other income
The Roth conversion stacks on top of whatever else you earn that year, so the same $40,000 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 | $2,620 (6.6%) | $780 (1.9%) |
| $25,000 | $4,730 (11.8%) | $3,440 (8.6%) |
| $50,000 | $7,150 (17.9%) | $4,660 (11.7%) |
| $100,000 | $9,164 (22.9%) | $5,500 (13.8%) |
| $150,000 | $9,600 (24.0%) | $8,800 (22.0%) |
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 | $2,620 | $2,620 |
| 60 | $2,620 | $2,620 |
| 66 | $1,654 | $1,654 |
| 73 | $1,654 | $1,654 |
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 | $598 | 1.5% |
| California | $548 | 1.4% |
| Maryland | $1,536 | 3.8% |
| Massachusetts | $1,780 | 4.5% |
| Michigan | $0 | 0.0% |
| North Carolina | $1,087 | 2.7% |
| Ohio | $650 | 1.6% |
| Pennsylvania | $0 | 0.0% |
| Virginia | $1,486 | 3.7% |
Spread over several years
Taking the same $40,000 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 | $2,620 | $7,150 |
| 2 years ($20,000 a year) | $780 | $5,500 |
| 4 years ($10,000 a year) | $0 | $4,800 |
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 $40,000 conversion adds about $6,284 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 Converted dollars withdrawn within five years before 59½ owe the 10% penalty, which is what a Roth conversion ladder plans around.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 |
|---|---|---|
| $20,000 | $390 on $20,000 | $390 on $20,000 |
| $25,000 | $890 on $25,000 | $890 on $25,000 |
| $30,000 | $1,420 on $30,000 | $1,420 on $30,000 |
| $40,000 | $2,620 on $40,000 | $2,620 |
| $50,000 | $3,820 on $50,000 | $3,820 on $50,000 |
| $60,000 | $5,020 on $60,000 | $5,020 on $60,000 |
| $70,000 | $6,570 on $70,000 | $6,570 on $70,000 |
| $75,000 | $7,670 on $75,000 | $7,670 on $75,000 |
| $80,000 | $8,770 on $80,000 | $8,770 on $80,000 |
| $90,000 | $10,970 on $90,000 | $10,970 on $90,000 |
| $100,000 | $13,170 on $100,000 | $13,170 on $100,000 |
| $125,000 | $18,734 on $125,000 | $18,734 on $125,000 |
| $150,000 | $24,734 on $150,000 | $24,734 on $150,000 |
| $200,000 | $36,734 on $200,000 | $36,734 on $200,000 |
| $250,000 | $51,304 on $250,000 | $51,304 on $250,000 |
| $300,000 | $68,134 on $300,000 | $68,134 on $300,000 |
| $400,000 | $103,134 on $400,000 | $103,134 on $400,000 |
| $500,000 | $138,134 on $500,000 | $138,134 on $500,000 |
The calculator, set to this Roth conversion
Set to a single filer aged 60 with $40,000 of Roth conversion and nothing else. Add Social Security, a pension, your state or a spouse.
On $40,000 of income, the 2026 tax is about $2,620: $2,620 federal. $0 of your Social Security is taxable. The next $1,000 you withdraw from an IRA would cost $120 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.