Coastful: FIRE Calculator

ZW Studio LLC

In-app purchases

About this app

Coastful is the Coast FIRE and retirement calculator built around YOUR portfolio. Project the year you can retire from real expenses, your real allocation, and the assumptions YOU choose. Whether you're planning Coast FIRE, Lean FIRE, or Fat FIRE, the math runs on your actual asset mix — not a textbook 4% rule.

★ COAST FIRE SIMULATION
Find the year you can stop contributing — and let compounding finish the job on time.

★ PERSONALIZED SAFE WITHDRAWAL RATE
A real-return SWR built from your actual asset mix, not a generic 4%. A mix that includes some lower-return holdings yields a more conservative SWR — and a more honest FIRE number.

★ INFLATION, MODELED
Every future dollar in your projection is discounted by inflation. The chart you see is real-dollar, not nominal. Tunable to match your view of the next decade.

★ WHAT-IF SCENARIOS
Three built-in scenarios show how a change today moves your FIRE year:
• Save more per month → years pulled forward
• Market drop pre- or post-FIRE → years delayed
• Upgrade or downgrade your home → years shifted

★ THE FREE CALCULATOR
• Your FIRE number from real annual expenses (classic 4% rule / 25× target).
• Funded percentage that updates as your portfolio grows.
• Multi-decade projection chart with the year your portfolio crosses the target.
• Net worth dashboard with year-over-year history and allocation by category.
• Unlimited assets and snapshots.
• Quick-update value with a one-tap pencil; batch-update at month-end.
• On-device backup and restore.
• Biometric app lock.

★ PRIVACY BY DESIGN
• Your data lives on your device. No backend account.
• No bank logins — you enter your own values.
• No ads. Anonymous usage analytics (Google Firebase) are opt-in and never include any financial amounts. Turn off in Settings, or reset/limit the advertising ID in Android system settings.
• Optional biometric lock on every launch.
• Exports and imports stay on your device.

What’s new

• A fresh new look: a cleaner, modern design with refreshed icons and Dark Mode support.
• A guided first-run tour: track your net worth and build your personalized FIRE plan.
• Personalized Safe Withdrawal Rate is now free — computed from your real asset mix.