Roth Conversion Planning Software
Model Tax Impact Year-by-Year. No Spreadsheets Required.
You know a Roth conversion ladder makes sense for your situation. You understand the tax arbitrage. What you need is software that can model the full impact: federal taxes this year, IRMAA brackets at 65, RMD reductions at 75, and long-term account balances.
Stop using spreadsheets that can’t handle the complexity.
Why Roth Conversions Matter (And Why Most Calculators Miss the Boat)
The 2026 TCJA expiration creates a 3-year window (2024-2026) where Roth conversions are significantly more valuable:
- Lower tax brackets expire December 31, 2025
- Standard deduction gets cut nearly in half
- OBBBA senior deduction (2026-2028) creates additional planning complexity
If you’re planning conversions for 2025-2028, your calculator needs to handle both TCJA expiration AND OBBBA. Most don’t.
What Fatboy Models (That Generic Calculators Can’t)
Full Multi-Year Conversion Analysis
- Model conversion amounts year-by-year from now through retirement
- See exactly how a $50k conversion in 2025 impacts:
- Your 2025 federal and state tax bill
- Your IRMAA brackets when you hit Medicare
- Your RMDs starting at 75
- Your total after-tax wealth at 90
IRMAA Threshold Management
Medicare premiums jump at specific income thresholds (IRMAA brackets). A poorly timed $5k conversion can cost you $2,000+ in extra premiums.
Fatboy shows IRMAA impacts for every conversion scenario - so you can stay under thresholds or deliberately breach them when it makes sense.
Tax Law Flexibility You Control
TCJA expires. OBBBA phases in. Tax laws will change again in 2027-2028.
You can edit tax brackets yourself. When Congress changes the rules, you update the parameters in 10 minutes and keep planning. No waiting 6-18 months for vendor updates.
Compare Strategies Side-by-Side
- Convert $40k/year for 5 years vs $100k in one big year
- Front-load conversions before TCJA expires vs spread evenly
- Roth conversions vs paying off mortgage early
- Different conversion amounts by tax bracket
See the tradeoffs. Understand the risks. Make informed decisions.
Real Roth Conversion Scenarios Fatboy Handles
Scenario 1: The TCJA Window (2024-2026) Convert while brackets are low, before expiration drives your rate from 22% to 25%
Scenario 2: The Early Retirement Conversion Ladder Retire at 55, live on taxable accounts, convert $50k/year at 12% bracket until Social Security starts
Scenario 3: The IRMAA Optimization Convert exactly up to IRMAA thresholds, maximize conversions without triggering premium surcharges
Scenario 4: The Mega Conversion Year One spouse retires, other still working, income drops - convert aggressively in the low-income year
Scenario 5: The RMD Minimization Strategy Convert enough pre-tax to Roth so your RMDs at 75 don’t push you into higher brackets or trigger IRMAA
How It Works
1. Enter Your Accounts Traditional IRA, Roth IRA, 401(k), taxable brokerage. Current balances and contribution plans.
2. Model Conversion Strategy Choose conversion amounts by year. Or let Fatboy suggest optimal amounts based on staying under specific tax brackets.
3. See Full Tax Impact Federal taxes, state taxes, IRMAA brackets, RMD projections. Every year from now through age 95.
4. Compare Alternatives Run multiple scenarios. Convert $30k vs $60k per year. Start now vs wait until retirement. See exactly what changes.
5. Stress Test Monte Carlo simulations show how conversions perform across thousands of market scenarios. Does your plan survive a 2008-style crash right after conversion?
Why Professional Planners Choose Fatboy for Roth Conversions
"I model Roth conversions for 30+ clients per year. Fatboy is the only software that handles TCJA expiration, IRMAA impacts, and editable state tax rates in one tool. When OBBBA passed, I updated my tax parameters in 10 minutes. Other advisors were stuck waiting for their vendors to update."
— Financial planner using Fatboy Pro for client deliverables
Not an advisor? You get the same tools they use - without the 1% AUM fee.
See Roth Conversion Analysis in Action
Compare scenarios: aggressive Roth conversions vs minimal conversions vs no conversions. See the after-tax difference at retirement.
Pricing: Own It Forever
Free Version: Full Roth conversion modeling. 3 scenarios. Core tax features. This isn’t a trial - it’s genuinely useful software.
Pro Version - $149 (One-Time):
- Unlimited scenarios (compare dozens of conversion strategies)
- IRMAA bracket optimization
- Advanced tax parameter editing (TCJA, OBBBA, state taxes)
- Professional PDF reports for your records or CPA review
- Monte Carlo simulations with conversion stress testing
- All future updates included
No subscriptions. You own it.
Compare that to:
- Financial advisor fees: 1% of $1M = $10,000/year forever
- Subscription software: $30-80/month = $360-960/year forever
- One CPA consultation on Roth conversions: $300-500 for 2 hours
Fatboy pays for itself immediately.
System Requirements
Windows 10/11 (fully supported) Linux (beta available) macOS (coming soon)
Desktop application. Your financial data stays on your computer. No cloud sync. No harvesting your information to train AI models.
Get Started with Roth Conversion Planning
Buy Pro Version - $149 (One-Time)
Try the free version. Model a few Roth conversion scenarios. See if the tax impact makes sense for your situation. Upgrade to Pro when you want unlimited scenarios and advanced features.
Frequently Asked Questions
Q: Can this handle both TCJA expiration (2026) and OBBBA senior deduction (2026-2028)? A: Yes. You can edit federal tax brackets yourself to model TCJA expiration, and the OBBBA senior deduction parameters are editable in Pro.
Q: Does it show IRMAA impacts? A: Yes. Fatboy calculates IRMAA brackets based on MAGI and shows premium surcharges for every year you’re on Medicare.
Q: Can I model state taxes? A: Yes. State tax brackets are fully editable. Model California’s 9.3% vs Texas’s 0% vs your state’s actual rates.
Q: What if tax laws change again after I buy it? A: You update the tax parameters yourself in the software. Takes 10 minutes. No waiting for vendors. This is why editable tax parameters matter.
Q: Can I share my analysis with my CPA? A: Yes. Pro version generates professional PDF reports you can email to your CPA or financial advisor for review.
Q: Does this give tax advice? A: No. This is planning software, not advice. It models scenarios and shows tax impacts. You (and optionally your CPA) make the decisions.
Questions? Email: fbfinancialplanner@gmail.com