You have three retirement questions a spreadsheet can't really answer. When could you afford to retire early? Could you take a year off to travel, study, or recover? Will you have enough at 65?

This planner answers all three in one place, with your numbers.

Why this, not a spreadsheet

Most retirement calculators are Google Sheets or Excel templates. You type your inputs into the cells, a formula runs, you stare at a single nest egg number, and you still don't really know what it means or how it got there.

This is different. Every result has a live calculation breakdown next to it. You can see exactly how your nest egg number was built from your own inputs, line by line. No black box.

A built-in historical backtest replays your plan against every 30-year market window from 1928 to 2023. Real S&P 500 returns adjusted for inflation. You get a concrete worst-case sentence like "starting in 1929, your portfolio ran out after 22 years," not a vague confidence percentage.

Three planners in one file

Switch between FIRE, career break, and traditional retirement instantly. Compare scenarios side by side. No separate apps, no separate purchases.

FIRE Architect: the early-retirement calculator

Hit your FIRE number at the savings rate you can actually sustain. Lean, Coast, and Fat FIRE variants are built in, plus a custom multiplier from 5x to 60x expenses. Inflation and a real-return assumption you control.

Sabbatical Planner: the career break calculator

Plan a 3 to 24-month break for travel, study, family, recovery, or a new direction. The app tells you exactly how much you need to save before launch, then tracks your progress against that gap fund as you check in over time.

Golden Years: the traditional 65+ retirement calculator

Models the nest egg you need based on what you want to spend, what Social Security or a pension will contribute, and when you stop working. Universal math, no US-specific tax assumptions, so it works anywhere in the world.

Show your work, every step

A live "show your work" panel sits next to every result. Watch the math build from your inputs in real time. The number stops being a black box.

95 years of market data, stress-tested against your plan

The historical backtest replays your plan against every 30-year window from 1928 to 2023 using real S&P 500 returns adjusted for inflation. Instead of a fuzzy "85% success" percentage, you get a concrete worst-case sentence: which starting year was the worst, and how long the portfolio lasted before it ran out.

Compare scenarios side by side

Save variations like "What if I save $500 more per month?" or "What if I retire at 62 instead of 65?" without losing your base plan. Compare up to three scenarios in a diff table that lays out the differences cleanly.

Track your progress over months and years

Log your current balance any time. The Tracker chart draws a real line through your check-ins so you can watch your plan come to life. Milestones (like "Halfway to nest egg") auto-generate and the editable checklist keeps the next step in front of you.

Privacy that actually works offline

The app makes no network requests. No analytics, no tracking, no "phone home." Your inputs, scenarios, and check-ins live in your browser's local storage on your machine. We have no copy of your data. We can't see it, recover it, or share it.

The trade-off: if you clear your browser data without backing up first, your data is gone. The Settings page includes Export Plan (saves to a JSON file) and Import Plan as your safety net. You control where the backup file lives. Dropbox, USB stick, email to yourself, anywhere.