About CoastFIRE Hub

I started investing in index funds in 2014 with no plan beyond “put money in, hope it grows.” Four years later, I stumbled on the concept of Coast FIRE and ran the math for the first time. The result surprised me: I had already crossed my Coast Threshold and did not know it.

That moment changed how I thought about work. I did not need to keep saving aggressively for retirement — compound interest was handling that. I could take a lower-paying job I actually liked, start a side project, or simply breathe easier knowing my retirement was already funded.

The problem was that every FIRE calculator I found either buried the answer in walls of text, asked for 30 inputs I did not have, or tried to sell me something. So I built the calculator I wished existed: one input screen, one answer, no account required, no data leaving my browser.

CoastFIRE Hub is that calculator, plus a few more tools for Barista FIRE, Fat FIRE, and comparing different FIRE paths. Every formula is open source. Every assumption is documented. Every number traces back to a primary source.

CoastFIRE Hub is a calculator toolkit built around one idea: your retirement math is simpler than the financial industry wants you to think.

The core tool is a Coast FIRE Calculator. You put in your age, current savings, annual spending, and target retirement age. It tells you your Coast FIRE number — the exact amount you need invested today so that compound interest finishes the job without another dollar of contributions from you.

There is also a Barista FIRE Calculator for part-time income scenarios, a Fat FIRE Calculator for higher spending targets, a universal FIRE Calculator, and a Coast FIRE Grid for quick lookups. More tools are added as the math warrants it.

For quick access, the CoastFIRE Hub Chrome Extension puts a fully functional Coast FIRE calculator in your browser toolbar — no accounts, no loading screens, no data leaves your device.

Every number on this site traces back to a primary source. No guessing, no rounding for convenience.

• 4% Safe Withdrawal Rate — Trinity Study (Cooley, Hubbard & Walz, 1998). A 4% withdrawal rate has historically been sustainable over 30-year periods for diversified portfolios.
• Market Returns — S&P 500 historical data: approximately 10% nominal annual returns since 1926 (source: officialdata.org).
• Inflation Rate — US CPI historical average: approximately 3% annually (source: Trading Economics).
• Real Returns — After inflation: approximately 7% annually. This is the default rate in all calculators.
• Average US Retirement Age — 61 years old (Gallup Survey, 2023).

Accuracy commitment: We review all data tables every 6 months. If you find a calculation error, email contact@coastfirehub.com and it will be corrected within 48 hours.

Last review: March 2026 | Next scheduled review: September 2026

The Coast FIRE calculation is two steps.

At $164,000 invested today, age 35, no further contributions needed. Compound interest handles the rest.

All calculators on this site use consistent assumptions: 7% real return, 4% SWR, 3% inflation, retirement age 65 in examples. Every input is adjustable.

The core calculation engine is open source: github.com/coastfirehub/fire-calculator