Choose Your Path

Try the planner free.
Buy Pro only if you want more depth.

Open the guided web app instantly with no signup and no credit card. Many planning tools are built around accounts, subscriptions, and cloud storage first. Fatboy is built around control first: start free, stay local-first, and upgrade to desktop plus optional encrypted sync only if you want more depth.

See the workflow before you pay anything.

Most visitors should start in the guided web app. It opens the main planner flow in the browser so you can test the inputs, the outputs, and the feel of the workflow before making a purchase decision.

Guided Web App Best for first-time visitors who want the real planner flow instead of being dropped into the teaser first.
Pro - $149 One-Time Best once you want to save work, compare scenarios, export results, and use the full desktop workflow.
Open The Guided Web App Open App / Quick Answer Buy Pro - $149

No subscription. No account required. No credit card to try it.

  • +Open instantly: runs in your browser with no install.
  • +Test a real plan: use the sample and adjust retirement timing, taxes, and withdrawals.
  • +Upgrade later if needed: additional scenarios and report exports are in Pro. Desktop also offers a separate 14-day trial.
Fatboy planner sample result showing projected savings balance over time
What opens when you click

The guided planner opens first so you can evaluate the real workflow, not just a teaser result.

Try Desktop Pro for 14 days

Evaluate longer-range scenarios, Roth conversion strategies, and stress tests on Windows or Linux. Download, request an emailed trial key inside the app, then activate. No credit card and no automatic charge.

Trial: up to 100 planning years and 1,000 Monte Carlo paths. Excel export and holdings import require a paid license. The 14 days start when your key is issued.

Download Desktop & See Trial Steps
Start Here

See it work before you pay.

Free

No account required | No credit card

The web app runs Python in your browser via Pyodide - no planning server receiving your numbers by default, and no account required to get started. Start with a sample plan, change your assumptions, and decide after you have seen the planner think through a real scenario.

Federal retirement fit: start with a federal sample plan and light pension / supplement inputs before deciding if you need the full workflow.

  • + All planning modules - Roth, IRMAA, goals, estate
  • + Works in any browser, any device
  • + Data stays in your browser - no server
  • + Federal sample plan + light pension / supplement inputs
  • - 1 scenario only
  • + Browser autosave and JSON plan import/export
  • - No PDF or Excel export
  • + Desktop has a separate 14-day Pro trial
Open The Guided Web App
Pro - Founding Member

Everything, everywhere.

$149 $249

Founding Member price | Increases to $249 at 200 users | One-time | Yours forever

Price increases to $249 after 200 Founding Members

Founding Member pricing

One license key unlocks the Windows desktop app, Linux desktop app, and the full web app. Use whichever fits the moment. Local-first by default, with optional encrypted cloud sync when you want it.

Buy if you want unlimited scenarios, saved plans, exports, deeper Monte Carlo testing, and full federal editing with advanced controls.

  • + Full web app - all modules, all devices
  • + Windows desktop app - full install, offline
  • + Linux desktop app - same full desktop app
  • + Full federal editing - deeper pension / supplement workflows
  • + Unlimited named scenarios - save and compare
  • + Save & load plans between sessions
  • + Export & import plan as JSON - portable across web and desktop
  • + Optional encrypted cloud sync - plan encrypted before upload, only you can read it
  • + PDF & Excel export
  • + Full Monte Carlo - all 7 market environments
  • + Breakpoint & stress test analysis
  • + Sensitivity analysis - tornado charts
  • + Editable tax parameters - model future law changes
  • + Estate & legacy forecasting
  • + Advanced Roth conversion optimizer
  • + Sankey cash flow diagrams
  • + Interactive goal solver
  • + All future updates - no upgrade fees
Buy Now - $149 Founding Member

Price increases to $249 after 200 Founding Members

Secure Stripe checkout | Direct email support

What You Can Actually Decide

Questions Fatboy Pro helps you answer.

Roth conversions

How much can I convert each year without creating a worse tax or IRMAA outcome later?

Retirement timing

What changes if I retire at 60, 62, 65, or phase out of work gradually instead?

Plan durability

Does this plan still work under weaker markets, higher spending, or future tax-law changes?

Sharing decisions

Can I export something clear enough to review with my spouse, CPA, or advisor?

Want to see how the output looks? View screenshots or read the comparison page before you buy.

This table describes the free web edition. The separate 14-day desktop trial enables advanced features with the limits listed above. After the desktop trial, saved plans remain available to view and copy; editing and new analyses require Pro.

What's Included

Free Full Web vs. paid Pro.

Feature Free Full Web Pro - $149
Core Planning
All planning modules++
Scenarios1 scenarioUnlimited
Planning horizonUp to 20 yearsUp to 100 years
Browser autosave & JSON plan files++
Federal retirement sample + light inputs++
Full federal editing + advanced controls - +
Tax & Roth Modeling
Basic tax projections++
IRMAA threshold modeling++
Roth conversion modeling++
Advanced Roth optimizer - +
Editable tax parameters - +
State tax modeling - +
Monte Carlo & Stress Testing
Monte Carlo simulations500 runsDesktop: up to 10,000 paths
Market environments1 (GBM baseline)All 7
Breakpoint analysis - +
Sensitivity analysis - +
Safe withdrawal rate analyzer - +
Visualization & Export
Sankey cash flow diagrams - +
Interactive goal solver - +
PDF report export - +
Excel export - +
Export / import plan as JSON++
Encrypted cloud sync (optional) - +
Estate & Legacy
Estate value projections - +
Legacy goal tracking - +
Inherited IRA RMD analysis - +
Estate tax exposure tracking - +
Platform
Web app (browser, any device)++
Windows desktop appSeparate free download + trial+
Linux desktop appSeparate free download + trial+
Offline useDesktop trial after activation+ (desktop)
Data stays on your device by default++
Optional cloud sync (client-side encrypted) - +
All future updates - + Free forever
Cost Comparison

$149 once vs. paying forever.

Software Year 1 Year 3 Year 5 Year 10
Fatboy - Founding Member $149 $149 $149 $149
Fatboy - Regular $249 $249 $249 $249
Boldin ($12/mo) $144 $432 $720 $1,440
ProjectionLab ($109/yr) $109 $327 $545 $1,090
Advisor fee (1% on $1M) $10,000 $30,000 $50,000 $100,000
FAQ

Common questions.

How does one license work for both desktop and web?

When you buy Pro, you get a single license key. Enter it in the desktop app's activation dialog, and enter the same key in the web app to unlock full access. One purchase, one key, both products.

Does the web app send my financial data anywhere?

Not by default. The web app runs Python locally in your browser using Pyodide - there's no server receiving your numbers. The only automatic network call is license key validation. Pro users can optionally enable cloud sync to back up and move plans across devices - but the plan is encrypted in your browser using your license key before it's uploaded. We receive ciphertext we cannot read. If you never use cloud sync, no financial data ever leaves your device. Full technical details ->

What is Founding Member pricing?

$149 is locked in for the first 200 users. Once we hit 200 Founding Members, the price will increase. If you're reading this, it's still available. Founding Members get all future updates free, forever.

Is there a trial before buying?

Yes. Use the free web planner without an account, or try Desktop Pro for 14 days. Install the desktop app, request a key with your name and email, then activate it. No credit card or automatic charge. The trial starts when the key is issued; Excel export and holdings import require purchase, and trial Monte Carlo is capped at 1,000 paths.

What platforms are supported?

The web app works in any modern browser on any device - Mac, iPad, Windows, Linux, Android. The desktop app is available for Windows 10/11 and Linux (portable archive). macOS desktop is on the roadmap.

What if tax laws change after I buy?

That's exactly what Fatboy is built for. You can edit federal and state tax parameters yourself - no waiting for a vendor update. When OBBBA passed in 2025, Fatboy users were updated in minutes. All updates are free for Pro users.

Can I share my plan with my CPA or spouse?

Yes. Pro includes PDF and Excel export, so you can generate professional-quality reports to review with a spouse, share with a CPA or tax advisor, or document your strategy for annual review.

What happens after I buy?

Checkout runs through Stripe. Then you get a receipt, your license key by email, download links for the desktop app, and immediate access to unlock Pro features in the web app.

What payment methods do you accept?

Credit cards and PayPal through Stripe. Secure checkout, nothing stored on our end.

$149 now. $249 after 200 users.

Best for people who want unlimited scenarios, exports, saved plans, and a tool they can keep using year after year.

Start in the guided web app first, or lock in Founding Member pricing for the complete planner, desktop app, and all future updates in one one-time purchase.

Buy Now - $149 Founding Member Open The Guided Web App Open App / Quick Answer

Founding Member price | Increases to $249 at 200 users | Desktop + Web included | All future updates free