Roth TSP vs Traditional TSP: Complete Tax Comparison Guide
Key Tax Differences Between Roth and Traditional TSP
The choice between Roth and Traditional TSP is one of the most important tax decisions federal employees make. Understanding the differences is crucial for maximizing your retirement savings.
| Feature | Traditional TSP | Roth TSP |
|---|---|---|
| Contributions | Pre-tax (reduces current taxable income) | After-tax (no current tax benefit) |
| Growth | Tax-deferred (taxed on withdrawal) | Tax-free (never taxed if qualified) |
| Withdrawals in Retirement | Fully taxable as ordinary income | Tax-free (if qualified: age 59.5+ and 5-year rule) |
| RMDs | Required starting at age 73 | No RMDs during original owner's lifetime |
| Agency Matching | Matches go to Traditional (always pre-tax) | Same - matches always go to Traditional |
| Best For | High earners expecting lower taxes in retirement | Young/low earners expecting higher taxes later |
When to Choose Traditional TSP
Traditional TSP makes sense in these situations:
Scenario 1: You're Currently in a High Tax Bracket
- Tax bracket 24% or higher: The immediate tax deduction saves you more money now than you'll likely pay in retirement
- Example: Contributing $10,000 to Traditional TSP at 24% marginal rate saves $2,400 in taxes today
- Retirement withdrawal: If you're in 12-15% bracket in retirement, you save the difference (9-12%)
Scenario 2: You Expect Lower Income in Retirement
- Typical pattern: Most retirees have lower income than their peak earning years
- FERS pension factor: Your FERS annuity provides baseline income, but may not fully replace your salary
- Social Security gap: Social Security typically replaces only 40% of pre-retirement income
Scenario 3: You Need Current Tax Relief
- High current expenses: Mortgage, children's education, caregiving costs
- State tax benefits: Reducing federal AGI may also reduce state taxes
- Other deductions phase-out: Lower AGI helps preserve other tax benefits
When to Choose Roth TSP
Roth TSP is advantageous in these situations:
Scenario 1: You're Early in Your Career
- Lower current income: GS-3 to GS-9 employees often in 10-12% brackets
- Long time horizon: 20-30+ years of tax-free growth compounds significantly
- Example: $5,000/year Roth contribution growing at 7% for 30 years = $472,000 tax-free
Scenario 2: You Expect Higher Future Tax Rates
- Legislative risk: Current tax rates are historically low; Congress may raise rates
- National debt concerns: Growing debt may force future tax increases
- Lock in current rates: Paying taxes now at known rates vs. unknown future rates
Scenario 3: You Want Tax Diversification
- Multiple tax buckets: Having both taxable (Traditional) and tax-free (Roth) sources provides flexibility
- Bracket management: Use Roth withdrawals to stay in lower tax brackets
- RMD hedge: Roth has no RMDs, reducing forced taxable income at age 73+
Scenario 4: Estate Planning Goals
- Tax-free inheritance: Heirs receive Roth balances tax-free (though they must take RMDs under SECURE Act)
- No RMDs during your lifetime: More flexibility for wealth transfer
- 10-year rule for heirs: Non-spouse beneficiaries must withdraw within 10 years, but withdrawals are tax-free
Roth TSP Qualified Withdrawal Rules
To withdraw from Roth TSP tax-free, you must meet BOTH requirements:
Requirement 1: Age 59.5 or Older
You must be at least 59.5 years old at the time of withdrawal. Exceptions exist for disability or death.
Requirement 2: 5-Year Rule
At least 5 years must have passed since your FIRST Roth TSP contribution. The clock starts on January 1st of the year you made your first Roth contribution.
| Situation | Contributions | Earnings |
|---|---|---|
| Age 59.5+ AND 5-year rule met | Tax-free | Tax-free |
| Under 59.5 OR 5-year rule not met | Tax-free (return of basis) | Taxable + 10% penalty |
| Disability or death | Tax-free | Tax-free (if 5-year rule met) |
Roth Conversion Strategies for TSP
If you have a large Traditional TSP balance, consider converting portions to Roth strategically.
In-Plan Roth Conversions
TSP allows in-plan Roth conversions, meaning you can convert Traditional TSP to Roth TSP while still employed:
- Taxable event: Converted amount is treated as taxable income in the year of conversion
- No 10% penalty: In-plan conversions avoid the early withdrawal penalty even if under 59.5
- 5-year clock restarts: Each conversion starts a new 5-year period for qualified withdrawals
Conversion Strategy Example
Case Study: Jennifer's Roth Conversion Ladder
- Age: 55
- Traditional TSP: $300,000
- FERS Pension (starting at 57): $35,000/year
- Goal: Reduce RMDs and create tax-free income source
Strategy: Convert $25,000/year from Traditional to Roth TSP for ages 55-62 (8 years)
- Total converted: $200,000
- Taxes paid: ~$3,000/year x 8 = $24,000 (in 12% bracket with FERS income)
- Roth balance at 73: ~$400,000+ (with growth)
- RMD avoided: ~$14,600/year less in forced withdrawals
- Lifetime tax savings: Estimated $50,000+ by avoiding 22-24% brackets
Contribution Limits for 2026
Both Traditional and Roth TSP share the same overall contribution limits:
| Limit Type | 2026 Amount | Notes |
|---|---|---|
| Employee elective deferral | $23,500 | Combined limit for Traditional + Roth employee contributions |
| Catch-up contribution (age 50+) | $7,500 | Additional amount for employees 50 and older |
| Total employee + agency contributions | $70,000 | Includes agency automatic 1% and matching contributions |
Optimal Contribution Split
Financial planners often recommend a diversified approach:
- Early career (GS-3 to GS-9): 70-100% Roth (lower tax bracket now)
- Mid-career (GS-10 to GS-13): 50/50 split (tax diversification)
- Late career (GS-14+): 70-100% Traditional (higher tax bracket now)
- Alternative strategy: Contribute enough to Traditional to stay in current tax bracket, rest to Roth