How it works
How the Roth Conversion Ladder Calculator works
Quick answer: Converting $40,000 a year from a $500,000 401(k) for 10 years moves $400,000 into a Roth IRA, with roughly $48,000 of tax at a 12% rate. Each conversion can be withdrawn without the 10% penalty after five tax years, so a 2026 conversion is available from January 1, 2031.
Formula
Total converted = yearly conversion × years
Estimated tax = total converted × 12%
Each conversion is withdrawable without the 10% penalty 5 tax years after the conversion year
The remaining 401(k) grows at the rate you enter, minus the amounts converted each year.
Worked example
$500,000 balance, $40,000 a year, 10 years, 7% growth. Converted $400,000; tax estimate $48,000; 401(k) left after 10 years $430,918.
$500,000 401(k), 10 years, 7% growth
| Yearly conversion | Total converted | Tax at 12% | 401(k) left | Open |
|---|
| $20,000 | $200,000 | $24,000 | $707,247 | Open |
| $30,000 | $300,000 | $36,000 | $569,082 | Open |
| $40,000 | $400,000 | $48,000 | $430,918 | Open |
| $50,000 | $500,000 | $60,000 | $292,753 | Open |
| $60,000 | $600,000 | $72,000 | $154,589 | Open |
Assumptions and limits
- Uses a flat 12% tax rate; conversions above the 12% bracket are taxed at higher rates.
- 401(k) money usually moves to a traditional IRA before converting; plan rules vary.
Frequently asked questions
How does a Roth conversion ladder work?
You convert 401k funds to Roth each year; each conversion becomes withdrawable penalty-free after 5 years.
Do I pay taxes on conversions?
Yes, conversions count as taxable income in the year you convert.
How does the 5-year rule work for conversions?
Each conversion has its own 5-year clock starting January 1 of the conversion year. Converted amounts withdrawn earlier, before age 59½, can owe a 10% additional tax.