Coast FI is the point where your invested assets are large enough that — without one more dollar contributed — compounding alone will carry you to retirement. Enter your numbers below and find yours.
This calculator uses your real return — growth minus fees minus inflation — so every figure you see is in today's dollars. The Coast FI Number assumes the 4% rule by default: enough invested that drawing 4% a year covers your retirement spending indefinitely. Adjust any of the assumptions and the projection updates live.
The Coast FI Calculator is a tool for informational purposes only. We do not guarantee the accuracy, reliability, or completeness of the results.
Most retirement math assumes you contribute every year until you stop working. Coast FI flips that. It asks: at what point would my current investments — left completely alone — grow to fund the retirement I want?
Reach that line, and you've earned an option. Keep contributing and retire early. Throttle back to part-time and let the principal coast. Take the lower-paying job that actually fits your life. The math has bought you choice.
It's not the only number that matters — there's still the question of bridging today and retirement age — but it's the first number worth knowing.
Coast FI tells you when your investments take over. It doesn't tell you how to bridge today to retirement, or how much working capital you'd need to actually walk away. The free Corporate Optional Worksheet walks you through all three sections — your Coast FI Number, your runway, and your launchpad capital — in about 30 minutes. It's the same worksheet I use in the first session of The Build.