FI Architect
A financial independence planner for real-world scenario modeling.
Use FI Architect to test assumptions, model tradeoffs, and plan your path to financial independence with more precision than a generic calculator — for free.
What it does
Model your financial independence path with real numbers.
FI Architect is designed for people who want more than a “years to retirement” estimate. It lets you test multiple scenarios, adjust assumptions, and understand how changes in savings rate, return assumptions, or spending targets actually affect your timeline.
- Scenario modeling — compare multiple FI paths side by side
- Assumption testing — see how sensitive your plan is to market returns
- Spending analysis — model different retirement spending levels
- Long-range projections — plan decades out with adjustable inputs
Two versions
Web App (Free)
The free web app runs in your browser — no signup, no download. Start modeling immediately.
Launch Free Web AppSpreadsheet (free)
The full workbook is now a free download. Customize assumptions, add your own scenarios, and keep the file permanently.
Download FI Architect Premium v4.8 →Now Available on iOS
FI Architect for iOS is live.
Deeper simulations, saved scenarios, progress tracking, and an AI co-pilot designed to help you think more clearly about your financial independence decisions — now available on the Apple App Store.
Download on the App Store →Access, data & support
Choose the version that fits how you plan.
Free browser app
Start with the sample plan for an immediate FI estimate, then replace the assumptions with your own. Your browser plan stays on this device unless you export it. No NJL account is required.
iOS and spreadsheet
The iOS app supports saved mobile planning and deeper guidance. The downloadable workbook is a file you control and customize. Review the privacy policy or contact support before entering sensitive information.
FI Architect is a planning and modeling tool. It is not financial advice. See full disclaimer.
Build record
From calculator to tested planning system
FI Architect began as a browser tool for making long-range financial decisions inspectable, then grew into a companion iOS product.
Why it exists
Scenario planning is more useful than pretending one retirement date or one forecast is certain.
How it was built
The workflow moved from browser modeling to saved iOS scenarios, AI-assisted planning, subscription handling, privacy surfaces, and App Store review preparation.
Where it stands
The web and iOS surfaces are released and evolving. The core calculator remains distinct from expanded AI workflows.
What proved difficult
A finished build did not prove App Store delivery. Privacy URLs, the real App Store app ID, paywall wording, Worker boundaries, and review evidence all had to be verified separately.
What happens next
Continue improving scenario clarity only when it improves household decisions; keep the educational and not-professional-advice boundary visible.