Most retirement calculators either oversimplify things or ask you to link your accounts so they can make money off your data. I wanted something that actually helped me see if I was on track without handing over a bank login, so I built RetireNumber. It's a privacy-first retirement planner. You type in your own numbers. No account linking, no selling your data, no VC. Just me and a subscription. The engine does real math: Monte Carlo with 1,000 runs, historical backtesting to 1928 using Shiller's Yale data, tax-aware withdrawal strategies, and scenario comparison so you can try different life paths. Whether you're still figuring out your number or you already have a target in mind, you can use it to get there or to check that your plan actually holds up.

You can try it without signing up: https://retirenumber.com/try. There's a demo mode and a short guided tour. Changelog and the full story are on the site if you want to dig in.

This isn't financial advice. It's just a tool for checking your number and whether your plan holds up. There is still a lot to but I'd love to hear whether the inputs and results feel clear and useful.

-Mark