A private, browser-based retirement tax planning engine — no server, no account, no data leaves your computer.
ROS™ is a comprehensive retirement income and tax planning application that runs entirely in your web browser. Open one HTML file, and you have a full-featured financial planning engine — complete with tax modeling, Social Security optimization, Roth conversion strategy, IRMAA Medicare management, investment allocation frameworks, and AI-assisted analysis.
Who is it for?
Anyone approaching or in retirement who wants to understand — at a deep level — how the US federal tax system interacts with their retirement income. You don't need to be a financial expert. Every field has a built-in explanation (hover the ? icon), and the built-in AI assistant can answer questions about your specific numbers in plain English.
What problems does it solve?
Most retirement calculators tell you how much money you'll have. ROS™ tells you how much of it you actually keep — after federal income tax, Virginia state tax, IRMAA Medicare surcharges, Required Minimum Distributions, Net Investment Income Tax, and all the other ways the tax code quietly takes a share of your retirement.
- Federal income tax: Full 2026 bracket table (MFJ / Single / MFS / HoH) with qualified dividend and long-term capital gain stacking
- IRMAA: Medicare Part B and Part D income-related surcharges — the "two-year lookback" trap and all five tier thresholds
- Social Security taxation: Provisional income formula — up to 85% of SS benefits can be taxable, and this is often misunderstood
- NIIT: Net Investment Income Tax (3.8%) trigger at $250K MAGI (married)
- Virginia state tax: 5.75% flat rate with Treasury interest exemption, SS partial exclusion, and home-state muni bond exemption
- RMDs: Required Minimum Distributions using IRS Uniform Lifetime Table, SECURE 2.0 age-75 rule
- 30-year projection: Year-by-year tax modeling for the full retirement horizon
- Annual Model: Full projection table — AGI, SS taxable amount, federal tax, NIIT, state tax, Roth conversions, end-of-year balances
- IRMAA Defense: Dedicated tab showing year-by-year Medicare premium exposure with buffer alerts
- Roth Conversion Engine: Schedule and optimize conversions — auto-fill to any bracket ceiling with one click
- Tax-Loss Harvesting (TLH): Carryforward tracking, ordinary income offset (the $3,000/yr rule), and net taxable gain modeling
- Dashboard: Six real-time KPIs updated instantly as you change any input
Choose from four evidence-based allocation strategies, each modeled with post-tax income estimates at your actual federal and state rates:
- Custom Bucket Plan — your own B1/B2/B3 allocation with full control
- All Weather (Dalio) — 4-regime risk balance (equities, bonds, gold, commodities)
- Permanent Portfolio (Browne) — equal 25% in four assets for all-season resilience
- Golden Butterfly — Permanent Portfolio plus a small-cap value tilt
Every instrument in the 26-entry Global Registry shows: gross yield → post-tax yield → IRMAA-visible income → tax drag. The numbers that matter, not the numbers that look good.
- Live yield fetching: Yahoo Finance (20 ETFs) + FRED Federal Reserve API (full Treasury curve)
- Manual override: Required for money-market funds like FDLXX and SPAXX (not available via APIs)
- History tracking: Up to 500 daily yield snapshots stored in your browser
- Portfolio tracker: Auto-snapshot of your total portfolio value each day
- Export/Import: Full JSON backup and CSV export — no database required
An interactive scenario engine where you can adjust:
- Portfolio balance, annual spending, guaranteed income (SS + pension + annuity)
- Planning horizon, inflation rate, fee drag, marginal tax rate, spending flexibility
- Bucket allocation (B1/B2/B3) and return assumptions
Real-time charts show 30-year portfolio trajectory across four named scenarios (Base Case, Conservative, Bad First 3 Years, Market Shock).
Four AI providers, configured once, work directly from your browser:
- Anthropic Claude (cloud) — highest-quality financial reasoning
- Google Gemini (cloud) — excellent for scenario exploration
- Groq (cloud) — fastest inference, free tier available
- Ollama (local, 100% private) — runs on your own hardware, zero data transmission
Twelve pre-built prompt templates for the most common retirement planning questions — IRMAA analysis, Roth optimization, RMD trajectory, Virginia domicile tax efficiency, sequence-of-returns stress test, and more.
- 24 wiki articles covering every concept from first principles — written for someone who has never studied tax law
- 159 HELP entries with three tiers: L1 hover (one sentence), L2 click (two-paragraph deep dive), L3 full technical detail
- Interactive demo (13 steps) — launches automatically on first open
- 44-page PDF reference guide — printable, structured, covers every field and formula
No installation required. No account. No internet connection needed to run the app.
Download ROS_v1.html from this repository.
Double-click the file, or drag it into Chrome, Firefox, Edge, or Safari.
Recommended: Chrome or Edge for best performance. The app uses React 18 (loaded from CDN on first open — after that it works offline).
The built-in 13-step demo launches automatically on first open. It walks you through every major feature with example numbers. You can re-launch it anytime from the sidebar → Demo button.
Go to Settings (sidebar) and enter:
- Filing status, state, annual spending
- Account balances (Taxable, IRA/401k, Roth)
- Person 1 and Person 2 details (birth year, retirement year, Social Security)
- Return assumptions
Every number updates every calculation instantly.
After the first load (which fetches React and Chart.js from CDN), the app works completely offline. No server calls are made for any calculation, AI features require internet access to cloud providers.
| File | Description |
|---|---|
ROS_v1.html |
The full application — this is all you need |
ROS_Reference.pdf |
44-page technical reference guide |
build_ros_pdf.py |
Python script that generates the reference PDF |
README.md |
This file |
LICENSE |
Proprietary license — see Usage Rights below |
CITATION.cff |
Structured citation for academic reference |
CONTRIBUTING.md |
How to report issues and request features |
.gitignore |
Git configuration |
ROS™ follows a single-file, zero-dependency, privacy-first design philosophy.
ROS_v1.html
├── Block 0: Data (wiki articles, rules engine, instrument registry)
└── Block 1: Application (React 18 UMD, Chart.js, all logic)
├── Tax Engine (federal, state, IRMAA, NIIT, SS, RMD)
├── Projection Engine (30-year deterministic + Monte Carlo)
├── Allocation Framework (Global Registry, 4 frameworks)
├── Yields System (Yahoo Finance, FRED, localStorage history)
├── What-If Engine (scenario modeling, bucket simulation)
├── AI Layer (Claude, Gemini, Groq, Ollama)
└── UI (React, Chart.js, dark/light mode, demo, wiki)
Why a single file?
- Zero deployment complexity
- Works from a USB drive, email attachment, or local folder
- No build step, no
npm install, no server - You can inspect every line of code — no black boxes
Data storage: All your data lives in your browser's localStorage. Nothing is transmitted to any server (except when you use a cloud AI provider — your financial data is included in the AI prompt, so use local Ollama if privacy is paramount).
All computations use 2026 tax parameters (codified as ROS-2026.1):
| Parameter | 2026 Value |
|---|---|
| Standard deduction (MFJ) | $30,000 |
| 22% bracket ceiling (MFJ) | $201,050 |
| 24% bracket ceiling (MFJ) | $383,900 |
| LTCG 0% ceiling (MFJ) | $96,700 |
| IRMAA Tier 1 threshold (MFJ) | $246,000 |
| IRMAA Tier 1 Part B surcharge | $74.00/mo per person |
| RMD start age (SECURE 2.0) | 75 (born after 1960) |
| NIIT threshold (MFJ) | $250,000 |
| Virginia flat rate | 5.75% |
| 401(k) contribution limit | $23,500 (under 50) / $34,750 (age 60–63, SECURE 2.0 super catch-up) |
Important limitation: Tax law is complex and changes frequently. ROS™ models the most impactful rules for retirement income planning but does not model every deduction, credit, phase-out, or state-specific provision. See the Known Limitations section and the in-app wiki article "Known Limitations & Approximations" for the full list.
If you're new to retirement tax planning, here are the four most important things to understand:
1. IRMAA — The Hidden Medicare Tax
Medicare Part B and Part D premiums increase in "tiers" based on your income from two years ago. In 2026, if your 2024 Modified Adjusted Gross Income was above $246,000 (married), you pay an extra $1,968/year per person on top of the base premium. The catch: crossing the threshold by $1 triggers the full tier surcharge — not a marginal increase. ROS™ shows your exact IRMAA exposure year by year, and alerts you when your MAGI buffer is dangerously thin.
Up to 85% of your Social Security benefit can be subject to federal income tax. Whether it is — and how much — depends on something called "Provisional Income": your AGI plus tax-exempt interest plus half your Social Security. Even income from federally tax-exempt municipal bonds counts toward this formula. ROS™ calculates the taxable portion each year using the exact IRS worksheet.
Between retirement and age 75 (when RMDs start), many people experience their lowest income years — no W-2, no Social Security yet, no Required Minimum Distributions. This is the Roth conversion window: the optimal time to move money from pre-tax IRA/401k accounts (where withdrawals will be taxed) into Roth IRA (where withdrawals are tax-free forever). ROS™ models conversions year by year and shows you the tax cost of each dollar converted vs. the long-term benefit.
The order in which investment returns arrive matters enormously. Getting poor returns in the first three to five years of retirement — when you're drawing down the portfolio to fund spending — is far more damaging than the same returns spread over the full retirement horizon. This is why ROS™ models a "Bad First 3 Years" scenario specifically, and why it emphasizes the B1 Liquidity Buffer (2–3 years of spending in cash/short bonds) as the primary defense.
ROS™ is designed from the ground up for maximum financial privacy.
- All tax calculations happen locally in your browser's JavaScript engine
- Your financial data is never transmitted to any server by the application itself
- The only external calls the app makes:
- CDN for React and Chart.js on first load (no data sent)
- Yahoo Finance API for live ETF yields (anonymous, no auth)
- FRED Federal Reserve API for Treasury rates (free API key, no financial data)
- Your chosen AI provider (if you use AI features — your plan data is included in prompts)
- All plan data is stored in
localStoragein your browser — it never leaves your device
For maximum privacy with AI features: Use Ollama (local AI) instead of cloud providers. Instructions are in the app under Settings → AI Configuration → Local Mode.
ROS™ is a powerful tool for retirement income planning, but it has deliberate simplifications. The in-app wiki covers these in detail; the most important ones:
- State tax: Models Virginia (5.75% flat). If you live in another state, the state tax calculation will be wrong. The federal calculations are state-agnostic and always accurate.
- Social Security COLA: Uses a fixed SS benefit; does not model annual cost-of-living adjustments.
- Investment returns: Assumes constant annual returns per bucket (no within-year volatility, no rebalancing friction).
- Tax law changes: TCJA brackets are modeled at their scheduled 2026 parameters. If Congress acts, thresholds change.
- Healthcare costs: IRMAA premiums are modeled; out-of-pocket medical expenses are not separately projected.
- Estate planning: No step-up in basis, estate tax, or trust structure modeling.
This is a planning tool, not a tax return. Always consult a qualified CPA or CFP before making significant financial decisions.
ROS™ was designed and built by Faiyaz Haider.
The tax rules engine incorporates 2026 IRS parameters, CMS IRMAA thresholds, and Social Security Administration benefit calculations — all from public government sources.
The four allocation frameworks draw on the published work of:
- Ray Dalio (Bridgewater Associates) — All Weather Portfolio methodology
- Harry Browne — Permanent Portfolio concept
- Tyler (Portfolio Charts) — Golden Butterfly variant analysis
No framework content is reproduced verbatim; the implementations are original code based on published allocation principles.
ROS™ is proprietary software. You may use it for personal financial planning. You may not redistribute it, sell it, or deploy it as a service. See LICENSE for complete terms.
Open a GitHub Issue to report bugs, suggest features, or ask about the modeling assumptions. See CONTRIBUTING.md for details on how to engage.
If you reference ROS™ in academic or professional writing, see CITATION.cff for the structured citation, or use:
Haider, F. (2026). Retirement Operating System™ (ROS™) [Browser-based retirement tax planning application]. https://github.com/[username]/ros
ROS™ and Retirement Operating System™ are trademarks of Faiyaz Haider. © 2026 Faiyaz Haider. All rights reserved.
