TSP Roth Conversion: Complete Guide
What is a Roth Conversion?
A Roth conversion allows you to move money from your Traditional TSP (pre-tax) to Roth TSP (after-tax). You pay income tax on the converted amount now, but qualified withdrawals in retirement are completely tax-free.
When Does Roth Conversion Make Sense?
✅ Good Candidates for Conversion
- Low Income Year: You're between jobs, took unpaid leave, or retired early before RMDs start
- Early Career: Your current tax bracket is lower than expected in retirement
- Tax Diversification: You want both taxable and tax-free income sources in retirement
- Estate Planning: You want to leave tax-free inheritance to heirs
- Avoid IRMAA: Strategic conversions can help manage Medicare premiums
❌ When to Avoid Conversion
- High Income Year: You're already in the 32%+ tax bracket
- Near Retirement: You'll have lower income (and tax rate) after retiring
- Can't Pay Taxes: You'd need to withdraw from TSP to pay the conversion tax (triggers penalty if under 59½)
- Medicaid Planning: Higher income could disqualify you from needs-based programs
Roth Conversion Tax Impact Calculator
Use this simple framework to estimate whether conversion makes sense:
Step 1: Determine your current marginal tax rate
Step 2: Estimate your retirement effective tax rate
Step 3: If Current Rate < Retirement Rate → Consider conversion
Step 4: Calculate break-even years
Example:
• Convert $50,000 from Traditional to Roth
• Current tax rate: 22%
• Tax due on conversion: $50,000 × 22% = $11,000
• Future value in 20 years at 7%: $193,484
• Tax-free withdrawal vs. taxed at 25%: Save $48,371
• Net benefit: $48,371 - $11,000 = $37,371
Conversion Strategies
Strategy 1: Fill the Tax Bracket
Convert just enough to "fill up" your current tax bracket without pushing into the next one.
| Filing Status | 12% Bracket Up To | 22% Bracket Up To |
|---|---|---|
| Single (2026) | $47,150 | $100,525 |
| Married Joint (2026) | $94,300 | $201,050 |
Strategy 2: Multi-Year Laddering
Spread conversions over several years to avoid pushing into a higher tax bracket in any single year.
- Year 1: Convert $40,000
- Year 2: Convert $40,000
- Year 3: Convert $40,000
- Total converted: $120,000 over 3 years
Strategy 3: Age 59½ to 73 Window
The "golden window" for conversions is between age 59½ (no early withdrawal penalty) and age 73 (when RMDs start).
Tax Implications
Immediate Tax Impact
The converted amount is treated as ordinary income in the year of conversion. This means:
- Your taxable income increases by the conversion amount
- You may push into a higher tax bracket
- Could affect eligibility for tax credits and deductions
- May trigger IRMAA (higher Medicare Part B premiums) if income exceeds thresholds
Long-Term Tax Benefits
- Tax-Free Growth: All future investment earnings are tax-free
- No RMDs: Roth TSP has no required minimum distributions during your lifetime
- Tax Diversification: Gives you flexibility to manage taxable income in retirement
- Estate Benefits: Heirs inherit tax-free withdrawals
Plan Your Complete Retirement Strategy
Roth conversion is just one piece. Calculate your full FERS benefits and TSP projections.