u/BrappZannigan

I got tired of calculators that spit out a number with no context, so I built www.myfirenum.com. No login, no account, no data collection, everything lives in your browser and stays there.

The design concept is a single scrolling page that tells your financial story. You enter your numbers at the top and as you scroll down it walks you through the full picture: your FIRE number, your debt payoff timeline, your portfolio lifecycle from accumulation through drawdown, tax strategy with a priority funding cascade that fills like buckets, Roth conversion ladder, sequence of returns Monte Carlo, Social Security break-even chart, income in retirement with age-aware withdrawal sequencing, also wired in six FIRE styles you can select. It's meant to feel less like a calculator and more like a financial plan laid out in front of you.

Everything is interactive: tap a number to edit it inline and the whole page recalculates.

Free, open to feedback, genuinely curious what's missing from your planning workflow.

www.myfirenum.com

Fellow physician here, most FIRE calculators give you a number and stop. I wanted something that actually helps think through the full plan, so I built myfirenum.com. It's free, no login, no data collection, everything stays in your browser.

I'm a visual learner so every section has interactive charts and visuals rather than just numbers. It covers the full picture: FIRE number and lifecycle chart, all six FIRE types, tax strategy with a priority funding cascade that fills like buckets, Roth conversion ladder with a tax bracket visualizer that fills up in real time as you adjust your conversion amount, sequence of returns risk with Monte Carlo simulation, Social Security claim age optimization with a break-even crossover chart, age-aware withdrawal sequencing, and a mortgage vs invest calculator that models the real opportunity cost of paying off cheap debt vs staying invested.

I got frustrated with tools that either oversimplified or required a financial advisor to interpret. Built this for myself and figured others might find it useful.

Genuinely open to feedback!

www.myfirenum.com

EDIT:

Thank you all for the feedback! I have been hard at work fixing and tweaking things based on your feedback and still have more to tackle as you guys find things that benefit you, I'm glad you are finding this tool helpful!

-Tap-to-edit sliders: tap any value and type an exact number instead of dragging.

-Coast FIRE completely reworked: now correctly models all three phases: save → let it compound → retire. Chart shows all three zones visually.

-Retirement spending separated from current spending: your FIRE number is now based on what you'll spend in retirement, not what you spend today.

-FIRE type multipliers fixed: Lean, Chubby, and Fat FIRE targets were mathematically wrong. Fixed.

-Part-time / spouse income: Barista and Coast users can now enter income that reduces their target and withdrawals.

-"Cannot reach FIRE" state: app now tells you clearly if your savings rate can't get you there. Various chart and calculation bug fixes throughout.

-Barista FIRE target completely reworked with correct three-phase math (accumulation → part-time bridge → full retirement)

-Added state income tax dropdown (all 50 states, default off)

-Added % mode to spending input — set savings rate as % of after-tax income