How this calculator works
The FIRE number equals annual retirement spending divided by a target withdrawal rate. The timeline then projects current investments and monthly contributions with a constant real return, meaning return after inflation.
FIRE is a planning target
A withdrawal-rate target is not a promise that a portfolio will support every retirement. Taxes, asset allocation, market sequence, health costs, benefits, geography, and flexible spending all change outcomes.
Real-world example
Annual spending of $50,000 divided by a 4% withdrawal rate produces a $1.25 million target. A 3.5% rate raises that target to about $1.43 million, showing how sensitive the estimate is to the chosen rate.
Common mistakes
- Using current spending without adjusting for retirement changes.
- Mixing nominal returns with today's-dollar spending.
- Treating the 4% rule as universal or guaranteed.
- Excluding taxes and irregular large expenses.
When to use this calculator
Use it to test a range of spending, withdrawal-rate, contribution, and real-return assumptions. A robust plan should work under more than one optimistic scenario.
FAQ
What does FIRE stand for?
Financial Independence, Retire Early—a planning approach centered on saving and investing enough to make paid work optional.
Is the 4% rule guaranteed?
No. It is a historical research-based starting point with assumptions and limitations, not a promise.
Why use a real return?
A real return removes assumed inflation so the target and timeline can remain in today's dollars.