Calculators
Free FIRE financial planner with Monte Carlo simulation and historical backtesting
Ahrefs Domain Rating set in type 6 Nov 2026, reset 5 Nov 2026.
A free browser-based retirement planning tool that models income, expenses, assets and life events with Monte Carlo simulation, historical backtesting, and tax
firenum™ is a free web application for FIRE (financial independence, retire early) planning. It runs entirely in your browser with no account required, letting users model their retirement by entering income, expenses, assets, debts and life events on a month-by-month basis.
The tool offers three ways to test retirement dates: average returns, Monte Carlo simulations with up to 5,000 runs, and historical backtesting against every market period since 1872. For US users, it calculates federal, state and payroll taxes for all 50 states, plus features like Roth conversion ladders, required minimum distributions, Social Security integration and ACA credit calculations.
Users can define up to five retirement plans side by side, apply six stress tests (market crash, job loss, inflation, early retirement, spending spike, and Social Security cuts), and choose from three withdrawal strategies. The tool supports nine currencies and works offline on Android phones. All financial data stays on the user's device in browser storage; nothing is sent to servers.
Pricing model: Free
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| Metric | Value |
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| Domain Rating | 12 no change since last check |
| Trust Flow | 4 no change since last check |
| Citation Flow | 34 no change since last check |
| Referring domains | 127 no change since last check |
| External backlinks | 832 no change since last check |
Ahrefs Domain Rating set in type 6 Nov 2026, reset 5 Nov 2026. Lead topic: Business/Publishing and Printing (3). Majestic set 5 Nov 2026, reset 5 Nov 2026. Link data typeset by Majestic. Trust Flow, Citation Flow and Topical Trust Flow are trademarks of Majestic-12 Ltd.
| Domain age | 10 months |
|---|---|
| Registered | |
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| Registrar | Cloudflare, Inc. |
| DNSSEC | Not signed |
Measured after firenum™ went live on Zivaro Launch on 5 November 2026.
Day 0 since launch. Next receipt: day 30, 5 Dec 2026. These are measurements, not proof of cause: many things move these numbers. Figures we have not measured are left out.
Free tips from Zivaro Launch for getting ready, launch day, the week after and what to do next.
Completely. firenum™ runs entirely in your browser with data saved in your device's localStorage. No account is needed, and without one no server stores your data. With a free account, plans are stored under your email and erased when you delete the account. Nothing is ever sold or shared, and aggregate traffic stats use cookieless Cloudflare analytics. You can export everything to CSV or clear it at any time.
Your FIRE number is the total amount of money you need invested to cover your living expenses indefinitely without working. It's calculated by multiplying your annual expenses by 25 (based on the 4% safe withdrawal rate). For example, if you spend $40,000 per year, your FIRE number is $1,000,000.
Yes, as a starting point. The 4% rule is based on historical U.S. market data and has a 95% success rate over 30-year periods. However, it's not a guarantee—it's a guideline. For early retirees with 40+ year retirements, consider using 3.5% for extra safety. The key is flexibility: if the market tanks early in your retirement, being willing to cut spending temporarily dramatically improves your odds.
No account needed, no email, no sign-up. Every calculator, the Fire Planner, all simulations, and the guides are fully usable with nothing locked away or held back behind a paid tier. A free account is optional: it keeps your plans on any device, and nothing is locked behind it.
The original Trinity study looked at 30-year periods. For longer retirements, you have options: use a more conservative 3-3.5% withdrawal rate (28-33x expenses), plan to earn some income in early retirement, or build in flexibility to reduce spending during market downturns. Historically, portfolios using the 4% rule often grew over 30 years rather than depleting, suggesting it works for longer periods too, but there are no guarantees.
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