A local net worth projection and financial event modeling tool. Create and compare multiple scenarios.
Got 30 seconds? Jump straight to the pre-rendered sample → and explore a working projection without installing anything.
New here? The Net Worth Navigator User Guide has full walkthroughs, explanations, and troubleshooting.
Returning users: retirement, Social Security claiming, and each person's modeled end of plan are now explicit, editable timeline events. The expanded six-tab Scenario Setup panel now exposes the full supported settings surface—Social Security benefit tables, income and contribution controls, richer accounts/liabilities, advanced simulation settings, and a visual Events workspace—so direct TOML editing is no longer required for normal scenario setup.
Existing scenarios retain legacy fallbacks, but use the Setup Panel's migration guidance (or update the event records in TOML) to adopt v2. See the User Guide for the updated workflow and the Event Types reference for the schema.
To preview that static demo from an unmerged local branch:
.venv\Scripts\python.exe scripts\build_demo.py --output-dir output\demo-preview
python -m http.server 8000 --directory output\demo-previewOpen http://localhost:8000. The demo build uses an isolated work directory and does not modify normal output\scenarios artifacts.
Net Worth Navigator projects your household net worth forward year by year, modeling compound growth, income, spending, taxes, loans, and life events. It answers questions like:
- Are we on track for retirement?
- What happens if one of us retires earlier?
- How long does the portfolio last at this spending level?
- What if we sell the house, move, or downsize later?
- What if Social Security starts at a different age?
Output is an interactive HTML page with Plotly charts, tables, and navigation tabs — viewable in any browser, no server required after rendering.
Three data source modes let you get started with or without financial accounts: Manual Entry (no accounts needed), Monarch Money live sync, or CSV import.
I was late to the retirement savings game.
The first part of my adult life was spent careening through a series of interesting, questionable, and financially unsound adventures far from my home country. I was 43 before I made my first 401(k) contribution.
I also grew up in a household where financial education simply was not a thing. No investing basics. No retirement planning. No explanation of what a 401(k) was supposed to do, or why compound interest was quietly judging me from the future.
So it took me a while to get my bearings.
As I got closer to my 60s, the vague anxiety started turning into specific questions. What kind of retirement could my wife and I reasonably plan for? Could we stay in the U.S. in the house we loved? Would we need to move overseas for a lower-cost life? What would happen if we retired earlier, later, spent more, spent less, downsized, or changed course?
The frustrating part was not that the questions were complicated. It was that I could not easily model them.
I tried several existing forecasting tools. Some were useful, but they tended to be one-size-fits-all, too limited, or locked behind another subscription. I already use and genuinely like Monarch Money, so I was particularly interested in its forecasting features. After trying them, however, I still found myself wanting more flexibility than I could justify paying extra for.
I wanted a retirement planner I could really tune: change an assumption, add a planned expense, shift a retirement date, adjust income, compare scenarios, and see the impact quickly. I did not want to fight a spreadsheet, re-enter the same numbers into a dozen calculators, or pay an ongoing subscription for something I might only use a few times a year.
So I started building Net Worth Navigator.
It began as a way to answer my own questions with more clarity and less guesswork. The goal is not to predict the future perfectly. The goal is to make the tradeoffs visible, test assumptions quickly, and turn retirement planning from a fog bank into something you can actually navigate.
I am not an accountant, financial planner, or professional software developer. Net Worth Navigator has therefore been developed with heavy AI assistance from Claude, GPT, and DeepSeek—but not without direction. I have spent a great deal of time defining the architecture, refining the behavior, troubleshooting problems, challenging assumptions, and reviewing the results. The project has been through multiple rounds of code and logic review, and I have made a serious effort to ensure that the calculations behave as intended. Even so, it should not be treated as professional financial advice, and I fully expect that people with deeper financial expertise may find areas that can be improved.
That caveat aside, if you find Net Work Navigator useful, please consider buying me a coffee to help offset the token costs my wife has been politely choosing not to ask about.
Net Worth Navigator is a good fit if you:
- want a strategic, year-by-year planning model rather than a monthly budgeting app
- want to test scenario changes — retirement timing, spending, home sale/purchase plans, recurring expenses, early-death cases
- are comfortable with simplified but improving tax modeling (bracket-based federal, state tax with 50-state support, RMD)
- want to run everything locally with no ongoing subscription fees
- want interactive charts you can share with a partner or advisor
It is not a full-fidelity financial planning system. See the User Guide for the full list of what it can and cannot do.
| Feature | Status |
|---|---|
| Household types: single-person and couples | ✅ Supported |
| Data sources: manual entry, Monarch Money live sync, CSV import | ✅ All three |
| Deterministic projection | ✅ |
| Monte Carlo simulation | ✅ |
| Historical return backtesting | ✅ |
| Withdrawal policy controls (cash targets, withdrawal order, surplus routing) | ✅ |
| Tax modeling (federal brackets, SS taxation, state tax with 50-state support, RMD) | ✅ |
| Event system with 10+ event types | ✅ |
| Recurring events and multi-person events | ✅ |
| Scenario comparison page | ✅ |
| Web-based configuration UI | ✅ |
| Config validation with actionable error messages | ✅ |
| Help mode with contextual tooltips | ✅ |
| Liabilities amortization and payoff tracking | ✅ |
| Cash reserve modeling and visualization | ✅ |
| Scenario cloning, renaming, deletion | ✅ |
| CSV account import | ✅ |
| Interactive Plotly HTML output (no server needed) | ✅ |
You need Python 3.11 or later. Download from python.org.
Windows: Check "Add Python to PATH" during installation. Linux: You may need sudo apt install python3-venv python3-pip.
git clone https://github.com/LemurTech/Net-Worth-Navigator.git
cd Net-Worth-NavigatorWindows: See the Git for Windows installation guide if you don't have Git. You can also download the repository as a ZIP.
Windows (PowerShell)
python -m venv .venv
.venv\Scripts\python.exe -m pip install -r requirements.txtLinux / macOS
python3 -m venv .venv
.venv/bin/python -m pip install -r requirements.txtWindows (PowerShell)
.venv\Scripts\python.exe scripts/verify_install.pyLinux / macOS
.venv/bin/python scripts/verify_install.pyYou should see [OK] All checks passed! at the end.
Once installed, head to the User Guide — Quick Start to try the sample scenarios and create your first own plan.
| Mode | Best For | How It Works |
|---|---|---|
| Manual Entry | First-time users, quick what-ifs | Enter account totals by type (cash, taxable, IRA, Roth, home) — no app subscription needed |
| CSV Import | Users with Monarch or compatible exports | Upload a CSV with Date, Account, Balance columns; classifications persist across imports |
| Monarch Money | Active Monarch subscribers | Live sync via MCP subprocess; automate with cron/Task Scheduler |
See the User Guide — Data Sources for full details and screenshots.
This project is designed to run in your home lab or on your personal computer. There is no authentication, no user management, and no access control. The web UI (when running) listens on localhost:8010 by default and serves anything in your project directory.
If you expose it to the internet — and I don't recommend it — your financial data and configuration are wide open.
Use common sense:
- Run the web UI only when you're actively editing configurations
- Don't forward port 8010 through your router
- Don't run
admin_app.pyon a shared or public network
Having trouble? The User Guide — Troubleshooting covers common issues including Python PATH, pip install failures, Windows Firewall, module errors, and more. You can also open an issue on GitHub.
If Net Worth Navigator has been useful to you — saved you time, gave you confidence in a decision, or just scratched an itch — please consider buying me a coffee.
This project took a lot of time and care, and I spent an embarrassing amount on API tokens during development. Every dollar helps offset those costs.
GNU General Public License v3.0 — see LICENSE for the full text.
This ensures that any distributed or modified versions (including network-service instances) remain free and open. You are free to use, modify, and share this software under the terms of the GPL v3.