About this site

Who runs this

FIRECalculatorHQ is built and run by one person: me, Jonas. No team, no content agency, no sponsor.

I started the site in early 2026 after shopping for a FIRE calculator and finding two kinds: ad-farms wrapped around a widget, and full planning suites that wanted an account before showing a single number. I wanted something in between, a calculator that answers one question well, instantly, and keeps your data on your side of the screen. So I built it.

Where the math comes from

Every calculator here runs on published research. Your FIRE number is annual spending divided by your withdrawal rate, the framework William Bengen published in 1994 and the Trinity Study stress-tested against a century of US market data. The safe withdrawal rate calculator uses the success-rate tables from the updated Trinity data (Cooley, Hubbard and Walz, 2011) cell by cell.

The projections are deliberately simple: year-by-year compounding with your savings added annually. Simple models are honest about being models. Defaults are conservative, every assumption is adjustable, and each page's FAQ says where the math cuts corners. Taxes, fees, and Social Security are yours to layer on top.

If a number looks wrong, email me and I'll check it against the sources. The whole site is version-controlled, so corrections ship fast.

Free calculators, paid products

The calculators are free and stay free: no ads, no affiliate links to brokers, no login. They run entirely in your browser, and the numbers you type are never sent to a server. The privacy policy has the details.

Two digital products pay the bills: a $27 ebook about the path out of mandatory work, and a $67 tax-planning workbook for US early retirees. If you buy one, thank you. If you don't, every calculator works exactly the same.

Contact

Email: jonaseriksenofficial@gmail.com. Bug reports jump the queue.

I'm not a financial advisor, and nothing on this site is financial advice.