Why Fatboy Financial Planner?

Tax laws change. Your retirement calculator shouldn’t be stuck in 2024.

The TCJA→OBBBA transition just proved exactly why Fatboy’s approach matters. Here’s what happened:

The TCJA Expiration Panic (2024)

December 2024:

Tax Cuts and Jobs Act (TCJA) set to expire December 31, 2025
Tax rates would increase from 22% to 25%, 24% to 28%
Standard deduction would drop from $29,200 to $15,000
Retirement planners panicked: “Should we convert to Roth now?”

Most retirement software: Hardcoded with 2024 tax rates. No way to model the expiration. Vendors promised updates “coming soon.”

Fatboy users: Edited tax parameters to model both scenarios. Saw exactly what TCJA expiration would cost. Made informed decisions about 2025 Roth conversions.

The OBBBA Surprise (July 2025)

July 4, 2025:

One Big Beautiful Bill Act (OBBBA) passes
TCJA brackets made PERMANENT (22% and 24% stay)
NEW $6,000 senior deduction added (2026-2028 only)
Estate tax exemption increased to $15M
TSP to Roth TSP conversions now allowed

This wasn’t the TCJA expiration everyone modeled. This was something different.

Most retirement software: Obsolete overnight. Still showing TCJA expiration scenarios. Waiting for vendor updates to add senior deduction. Users stuck with wrong numbers.

Fatboy users: Updated tax parameters themselves within hours. Modeled the new senior deduction. Ran 2026-2028 conversion scenarios immediately. Kept planning while everyone else waited.

What This Proves

Tax law changes are not hypothetical. They’re constant.

In the last 20 years:

2001: EGTRRA passed (Bush tax cuts)
2003: JGTRRA passed (capital gains changes)
2010: Tax Relief Act (estate tax changes)
2012: ATRA passed (fiscal cliff resolution)
2017: TCJA passed (major overhaul)
2025: OBBBA passed (TCJA extension + new provisions)

That’s a major tax law change every 3-4 years.

And every time, hardcoded retirement calculators become obsolete for 6-18 months while vendors scramble to update.

The Hardcoded Software Problem

Most retirement planning tools work like this:

Vendor hardcodes 2024 tax rates into software
User runs retirement projections (assuming 2024 rates forever)
Tax law changes
Software is now wrong
User waits 6-18 months for vendor update
Vendor finally updates (maybe)
Repeat when next tax law changes

Problems with this approach:

❌ You’re planning with outdated assumptions Your 2027 retirement plan assumes 2024 tax rates that don’t exist anymore.

❌ You can’t model “what if” scenarios What if Congress changes tax rates in 2027? You have no way to model it.

❌ You’re dependent on vendor updates Your $100/year subscription gets you… waiting for updates.

❌ Your plan is always 1-2 years behind current law By the time software updates, the law has changed again.

The Fatboy Approach

Fatboy works differently:

Tax parameters are editable by you
- Tax brackets (by year)
- Standard deduction (by year)
- Personal exemptions (toggle on/off)
- IRMAA thresholds
- RMD age requirements
- All major tax parameters
You model scenarios yourself
- Scenario A: Current law continues
- Scenario B: TCJA expires as scheduled
- Scenario C: OBBBA passes (what actually happened)
- Scenario D: Future changes you anticipate
You update immediately when laws change
- OBBBA passes July 4, 2025
- You read the law (or our blog)
- You update tax parameters
- You’re modeling accurately within hours
You’re never dependent on vendor updates
- No waiting 6-18 months
- No being stuck with wrong numbers
- No hoping the vendor eventually updates

Real Example: OBBBA Senior Deduction

The OBBBA senior deduction is temporary (2026-2028 only).

This creates a critical 3-year window for Roth conversions where:

You get an extra $6,000-$12,000 deduction
Conversions are 10-20% cheaper than in 2029+
Strategic timing can save $3,000-$10,000 in taxes

Most retirement calculators:

Don’t have senior deduction coded yet (as of January 2026)
When they add it, might not code the 2028 sunset correctly
Might show senior deduction forever (wrong)
Or might not show it at all (also wrong)
Users making $100,000+ decisions based on wrong math

Fatboy approach:

Edit standard deduction for 2026-2028: Add $12,000 (senior deduction)
Edit standard deduction for 2029+: Back to $31,500 (senior deduction expired)
Run Roth conversion scenarios comparing 2026-2028 vs 2029+
See exactly how much the senior deduction saves
Make informed decisions about conversion timing

Same-day accuracy. No vendor update required.

What Happens When the Next Tax Law Changes?

Because it will. Probably in 2027-2028.

Possible changes on the horizon:

OBBBA senior deduction expires 2028 (guaranteed)
Social Security funding crisis (2034 trust fund depletion)
Capital gains rate changes (frequently proposed)
IRMAA bracket adjustments (happens constantly)
RMD age increases (changed twice in 5 years)
Estate tax exemption changes (political football)

With hardcoded software: You’re stuck until vendor updates. Months of planning paralysis.

With Fatboy: You edit the parameters yourself. Keep planning through the uncertainty.

“But I Don’t Know What Future Tax Rates Will Be”

Neither do we. Neither does anyone.

That’s exactly why you need scenario modeling, not hardcoded assumptions.

Example: TCJA Expiration Planning (2024)

Hardcoded software approach: “TCJA will expire December 31, 2025. Here’s your plan assuming 2017 tax rates return.”

Problem: That’s not what happened. OBBBA passed instead. Your plan is wrong.

Fatboy approach: Run three scenarios:

Scenario A: TCJA expires as scheduled (25%, 28% brackets)
Scenario B: TCJA extended permanently (22%, 24% brackets)
Scenario C: Partial extension or modification (mix of rates)

Compare all three. See which strategies work in ALL scenarios. Make robust decisions that work regardless of what Congress does.

When OBBBA actually passed:

Closest to Scenario B (permanent TCJA rates)
But with additions (senior deduction)
Easy to update Scenario B with senior deduction
Strategies were already robust across scenarios

This is how professional financial planners work. They don’t assume one future. They model multiple futures and find strategies that work across scenarios.

The “Edit Your Own Tax Parameters” Advantage

Five real situations where this mattered:

1. TCJA Expiration Uncertainty (2024-2025)

Users modeled expiration vs extension. Made Roth conversion decisions robust to both outcomes.

2. OBBBA Senior Deduction (2025)

Users added $12,000 senior deduction for 2026-2028, removed it for 2029+. Saw the conversion timing advantage immediately.

3. State Tax Planning

User moving from California (13.3% top rate) to Florida (0% tax). Edited state tax rate by year. Saw exactly when to do Roth conversions.

4. IRMAA Bracket Management

User edited future IRMAA thresholds to account for inflation adjustments. Found conversion amounts that avoided future Medicare premium cliffs.

5. Conservative Tax Planning

User assumes tax rates will increase 20% by 2035 (deficit concerns). Edited brackets higher for future years. Stress-tested retirement plan against higher taxes.

None of these are possible with hardcoded software.

“What If I Edit Something Wrong?”

Valid concern. Three protections:

1. Default to Current Law

Software ships with current 2026 OBBBA tax parameters. If you don’t edit anything, you’re using current law.

2. Reset to Defaults

One-click reset back to official current law parameters. Undo any edits instantly.

3. Scenario Comparison

Edit parameters in Scenario B while keeping Scenario A at defaults. Compare side-by-side. See the impact of your changes.

The alternative is worse: Trusting a black box with hardcoded parameters you can’t see, can’t verify, and can’t update when wrong.

At least with editable parameters, you control what you’re modeling.

The Tax Law Change Guarantee

We guarantee tax law will change again.

Maybe in 2027. Maybe 2028. Definitely before you retire.

When it does:

Hardcoded software users:

Wait 6-18 months for vendor updates
Plan with outdated numbers
Make decisions based on wrong assumptions
Hope the vendor eventually updates correctly

Fatboy users:

Read our blog post explaining the changes (published within days)
Update tax parameters yourself (takes 10 minutes)
Run new scenarios immediately
Make decisions based on current law

This is why professional financial planners use software with editable parameters.

They don’t wait for vendor updates. They model the changes themselves.

What About Other Features?

Yes, Fatboy does everything else retirement software should do:

✓ Monte Carlo simulations (sequence of returns risk) ✓ Roth conversion optimization ✓ IRMAA bracket analysis ✓ RMD calculations ✓ Social Security optimization ✓ Tax bracket management ✓ Withdrawal sequencing ✓ Scenario comparison

But the editable tax parameters are what make all of those features actually useful.

What good is a Roth conversion optimizer if it’s using 2024 tax rates in 2027?

What good is IRMAA analysis if it’s using outdated Medicare brackets?

What good is long-term planning if tax assumptions are frozen in time?

The TCJA→OBBBA Case Study

December 2024: Most retirement software: “TCJA expires in 12 months. Your taxes are going up 20-30%.”

Fatboy blog: “TCJA Expiration 2026: The Tax Bomb Nobody’s Modeling” Explained what expiration would mean. Showed users how to model it. Recommended hedging strategies.

July 2025: OBBBA passes. TCJA made permanent. New senior deduction added (2026-2028).

Most retirement software: Obsolete. Wrong numbers. Waiting for updates.

Fatboy blog: “OBBBA Changes Everything” Published within days. Explained new law. Showed exactly which parameters to update.

Fatboy users: Updated parameters. Modeling new law accurately within hours.

This is the advantage of editable parameters + expert analysis.

You’re never stuck. You’re never waiting. You’re never planning with outdated numbers.

“But I’m Not a Tax Expert”

You don’t need to be.

You need to:

Read our blog posts (we explain the changes in plain English)
Follow the parameter update instructions
Run the scenarios we recommend

Example: OBBBA Senior Deduction Update

Our blog post said: “Edit standard deduction for 2026-2028: Add $12,000 (married, both 65+). Set it back to regular standard deduction for 2029+. Then run Roth conversion scenarios for 2026-2028 vs 2029+ to see the tax savings.”

You do:

Open tax parameters
Edit standard deduction 2026: $31,500 + $12,000 = $43,500
Edit standard deduction 2027: $43,500 (with inflation)
Edit standard deduction 2028: $43,500 (with inflation)
Edit standard deduction 2029: $31,500 (senior deduction expired)
Save
Run scenarios

Takes 5 minutes. You’re now modeling current law accurately.

Compare that to waiting 12 months for your vendor to maybe update their software.

Who This Is For

Fatboy Financial Planner is built for people who:

✓ Want to control their own retirement planning ✓ Don’t trust black box calculators ✓ Need to model tax law changes ✓ Value accuracy over simplicity ✓ Are willing to learn (but don’t need a PhD) ✓ Want software that doesn’t become obsolete every time Congress passes a bill

This is NOT for people who:

❌ Want a “set it and forget it” calculator ❌ Trust vendor updates to always be timely and correct ❌ Don’t care about tax optimization ❌ Are satisfied with generic retirement advice

The Bottom Line

Tax laws changed in 2025. They’ll change again in 2027 or 2028.

When they do, do you want to:

Option A: Wait 6-18 months for your retirement software vendor to update? Plan with outdated numbers in the meantime? Hope they eventually get it right?

Option B: Update the parameters yourself in 10 minutes? Keep planning through the uncertainty? Model multiple scenarios to hedge against legislative risk?

Fatboy is Option B.

Because retirement planning with frozen tax assumptions isn’t planning. It’s hoping Congress never changes anything.

And the TCJA→OBBBA transition just proved that hope is not a strategy.

Get Started

Download the free version. See how editable tax parameters work. Model OBBBA senior deduction scenarios yourself.

Download Free Version

Upgrade to Pro when you need unlimited scenarios, advanced Monte Carlo controls, and professional PDF reports.

See Pricing

Read the OBBBA analysis to understand current tax law and optimal 2026-2028 strategies.

Read: OBBBA Changes Everything

Questions? Email: fbfinancialplanner@gmail.com