When to do Roth conversions,
using low-income years.
Roth conversions are not just for the five-year ladder. Any year your income is lower than usual is a window to convert Traditional IRA or 401(k) money to Roth at a lower tax rate. This page covers how to find your window and fill the right brackets without tripping secondary taxes.
Identify years when your taxable income is lower than normal. Convert Traditional money to Roth up to the top of your current bracket. Pay tax now at the lower rate rather than later at the higher rate. Coordinate with capital-gain harvesting: both use the same low-bracket space. Watch for ACA subsidies, IRMAA, and Social Security taxation.
The bracket-filling approach
The goal is to fill lower brackets, not convert everything at once.
- Ordinary income: $30,000
- Standard deduction: $16,100
- Taxable income: $13,900
- 12% bracket goes to $48,475
- Empty bracket space: $34,575
- Convert $34,575 of traditional to Roth at 12% marginal rate
- Tax: ~$4,149
- Without conversion, that money would later be withdrawn in a year when income might be higher
Windows to target
- Early retirement before Social Security. Lowest-income years of adult life. Deferring SS to age 70 extends the window. Convert aggressively.
- Career gap. Taking time off between jobs. Lower income, lower brackets.
- Sabbatical year.
- Year of significant deductions. Large charitable gift, business loss, major medical above threshold.
- Market downturn. Convert after a drop. You pay tax on a lower value. Recovery happens inside the Roth, tax-free.
What to watch for
Roth conversion counts as income. Can push you above ACA subsidy thresholds and dramatically raise healthcare costs for the year verify×DON'T TRUST, VERIFYClaim: Modified AGI including Roth conversions counts toward ACA subsidy eligibility.Verify at: healthcare.gov ↗ACA uses MAGI. Conversions flow through.. Model before converting.
A high conversion year can trigger Medicare IRMAA surcharges two years later verify×DON'T TRUST, VERIFYClaim: IRMAA uses Modified AGI from 2 years prior to determine Medicare Part B and D surcharges.Verify at: medicare.gov ↗ and SSA IRMAA ↗Two-year lookback with life-change event appeal available.. Plan ahead.
Provisional income includes Roth conversions. Can push SS benefits into taxable territory (up to 85% taxable).
Do not stack in the same year if you can avoid it. Both add to taxable income. One large-income year vs two moderate years is usually more tax-efficient.
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Last updated 2026-04-22. Not financial or tax advice.
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