About

Who Built This, and Why

One person, a real retirement-planning problem, and a refusal to choose between oversimplified free calculators and $144-a-year subscriptions.

4 min readLast reviewed July 2026

I built this because I needed it.

Why this exists

Most retirement calculators are either too simple or too complicated. The free ones miss the math that actually matters — Social Security filing strategy, spouse coordination, tax drag, sequence-of-returns risk. The professional software gets it right, but it's slow, expensive, behind a login, and built for advisors managing client portfolios — not someone who just wants to run a few scenarios on a Sunday afternoon.

So I built something in between. It's free to use. The AI Advisor is $79, once.

Every assumption in this tool is documented in the methodology — formulas, source data, tax brackets, Monte Carlo distribution. Nothing is hidden.

Who built it

My name is Luke Newton. I have a software and financial services background, and I've spent enough time around retirement planning to know what good math looks like — and what shortcuts to avoid. I'm not a financial company, a fintech startup, or a registered investment advisor. I'm someone who spent time and money solving a problem I had, and figured others might find it useful too. This is a tool I'd want to exist — so I built it.

You can find me on Reddit as u/lnewton_me, where I'm active in r/DIYRetirement, r/Fire, r/ChubbyFIRE, and a few other personal-finance communities. If you've got a question and would rather ask it publicly, that's a good place to flag me.

How the math stays honest

A solo-built financial tool earns trust differently than a company does: by showing its work. Every formula the engine uses is published. The simulation is seeded, so identical inputs always produce identical outputs — which makes the whole engine testable. Before any release, an automated 19-gate verification pipeline re-runs 27 benchmark retirement scenarios and fails the release on a single dollar of unexplained drift. The full regime — what's tested, what's not, and every fidelity change with dates — is public in the trust framework.

How the pricing works

The app and everything it produces — your projections, your scenarios, your Social Security analysis — is free. I only charge when you want the AI Advisor to read your plan and give you specific recommendations. That's Navigator — $79, once, with 25 deep AI analyses and 50 conversations included. (If you run out, Advisor Plus is $29 and adds 10 more deep analyses plus 25 more conversations; Advisor 365 at $79 for 365 days unlocks unrestricted AI access for the year, though most never need that.) The AI costs real money to run, so I charge for it. No required subscription.

I'd genuinely rather more people use this for free than pay me. If it helps someone retire smarter, that's the point. The money keeps the lights on.

On your data

There's no account, no server storing your numbers, no database holding your plan — it lives in your browser. The one exception is the AI Advisor: when you use it, anonymized numbers go out to generate your reply, then they're gone. Otherwise nothing you enter reaches me — I don't even require an account.

The export is designed to be useful on its own — or as preparation for a conversation with a financial advisor.

Get in touch

Questions, bug reports, feature requests, or just telling me how your plan looks — all welcome. Use the contact form at the bottom of the homepage. I read every message and reply to most.

The best introduction is just running your own numbers — free, five minutes, no account, nothing leaves your browser.

Run your plan free →